—  • — •• — " — •• — " — rwt^i — n — n^_n — n — n — rt_fi__n_-n_-ft— n— fv 

REESE  LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 

^Received  yl/ldAJ'         •  > 

Accessions  No.  lf>5D  J J  .     c/js.v  M). 


r— u— u— J 


ROADS  AND  PAVEMENTS 


IN 


FRANCE. 


BT 

ALFRED  PERKINS  ROCKWELL,  A.M.,  PH.B. 

formerly  Professor  of  Mining  at  the 

Sheffield  Scientific  School  and  at  the  Massachusetts 

Institute  of  Tecknvlogy, 


FIRST    EDITION. 

FIRST   THOUSAND. 


f        *  OF  THE  ^        >V 

(UNIVERSITY) 

V.  OF  ^f 


NEW   YORK: 

JOHN    WILEY   &   SONS. 

LONDON:    CHAPMAN  &   HALL,   LIMITED. 

1896. 


COPYRIGHT,   1895, 

BY 
JOHN   WILEY  &  SONS. 


BRAUNWORTH,    MUNN    A    BARBER,    PRINTERS    AND    BOOKBINDERS,    NEW    YORK. 


€         OF  THE  *^       \. 

IVERSITY) 
OF  S 

_*^u4r  w1^1    ti^^ 


PREFACE. 


THIS  contribution  to  the  literature  of  Road  Making 
will,  it  is  believed,  be  of  service  to  all  who  are  inter- 
ested in  the  improvement  of  our  highways  both  in  the 
city  and  in  the  country.  It  is  partly  the  result  of 
personal  observation  by  the  writer,  but  is  mainly  a 
compilation  from  the  standard  publications  of  Mon- 
sieur A.  Debauve,  Ingenieur  en  Chef  des  Fonts  et 
Chaussees  in  charge  of  the  Departement  de  1'Oise,  and 
from  the  official  documents  of  the  French  Government. 

The  writer  desires  to  express  his  obligations  to  the 
several  friends  who  have  aided  him  in  various  ways, 
and  more  especially  to  M.  A.  Debauve,  Ingenieur  en 
Chef  des  Fonts  et  Chaussees;  M.  F.  Guillain,  Inspec- 
teur  General  des  Fonts  et  Chaussees,  Conseiller  d'Etat ; 
M.  Boreux,  Ingenieur  en  Chef  des  Fonts  et  Chaussees 
et  de  la  Voirie  de  Paris;  and  Prof.  C.  Frank  Allen, 
Massachusetts  Institute  of  Technology,  for  courteous 
assistance  and  valuable  material. 

ALFRED  PERKINS  ROCKWELL. 

BOSTON,  October  1895. 

iii 


CONTENTS. 


PAGE 

Historical i 

A  perfect  wagon-road 4 

Grade 8 

Material  for  roads,  gravel n 

Broken  stone • 12 

Scale  of  quality 13 

Quality  of  various  rocks  used 14 

Quality  used  on  Routes  Nationales 15 

Preparation,  cleanness,  size  of  stone 16 

Mode  of  construction 17 

Gravel  road 18 

Stone  road 18 

Roads  with  foundation 19 

Tresaguet's  method 20 

Telford's  system 21 

Roads  without  foundation 23 

Macadam's  system 24 

Thickness  on  Routes  Nationales 26 

Binding  material 28 

Reduction  of  bulk 30 

Convexity,  crowning 31 

Resume  of  process  of  construction ...  33 

Maintenance  and  repair 36 

Patchwork  repair 37 

Repair  of  tracks  and  ruts 40 

General  recharging 41 

Thickness  of  rechargings 43 

Picking  surface  for  recharging 44 

Rolling ' 45 

v 


vi  CONTENTS. 

PAGE 

Watering  during  rolling .   46 

Modified  recharging 50 

Scraping  and  sweeping 51 

Typical  French  roads 51 

Tree  plantations 56 

Cost  of  construction  in  the  United  States 59 

Cost  of  construction  in  France 60 

Cost  of  maintenance,  Routes  Nationales 64 

Unit  of  travel 65 

Pavements  of  Paris 69 

Service  of  the  public  ways 70 

Different  classes  of  streets 71 

Foundation  for  pavements 72 

Different  kinds  of  pavement 73 

Block-stone  pavement 76 

Macadam  pavement 81 

Asphalt  pavement 84 

Asphalt  sidewalks 88 

Wood  pavement 91 

Cleaning  and  watering  streets 98 

Removal  of  house-refuse 99 

Street-sweeping 101 

Watering  of  streets 103 

Width  and  convexity  of  Paris  streets 104 

Classification  of  French  roads 106 


ROADS    AND    PAVEMENTS   IN   FRANCE, 


HISTORICAL. 

THE  history  of  roads  in  Europe  is  interesting  as  be- 
ing in  short  the  history  of  civilization.  The  condition 
of  the  means  of  communication  reflects  fairly  well  the 
general  state  of  society  during  the  successive  centuries. 

The  Romans,  as  every  one  knows,  were  the  first 
great  road-builders.  By  means  of  their  wonderful 
system  of  permanent  highways,  reaching  from  Rome 
to  every  part  of  the  vast  empire,  and  over  which  their 
great  armies  moved,  they  held  in  subjection  every  prov- 
ince and  planted  their  civilization  in  the  heart  of  each 
conquered  people.  With  the  breaking  up  of  the 
empire  and  the  invasion  of  the  barbarians  came  a  great 
change  in  the  conditions  and  requirements.  The 
necessity  which  created  these  great  highways  ceased 
in  a  measure,  and  the  roads  were  no  longer  maintained. 
Such  solid  work  was  not  indeed  destroyed,  but  in  time 
it  simply  deteriorated  from  neglect. 

Later  Charlemagne   did   much   to  restore  them   to 


2  ROADS  AND   PA  VEMENTS  IN  FRANCE, 

good  order,  as  he,  like  the  Romans,  had  large  armies 
to  move  rapidly  over  great  distances. 

Later  again,  under  his  weaker  successors  and  still 
more  under  the  feudal  system  which  followed,  the 
roads  were  almost  entirely  neglected,  and  their  deteri- 
oration was  well-nigh  complete.  The  feudal  lords  in 
some  cases,  it  is  true,  maintained  them  within  their 
several  domains,  but  more  often  neglected  them,  and 
in  fact  sometimes  actually  destroyed  them,  the  better 
to  defend  their  territories  against  more  powerful  neigh- 
bors. Moreover  the  state  of  society  in  the  Middle 
Ages  did  not  demand  good  roads.  Carriages  for  per- 
sonal travel  were  but  little  used,  as  the  great  lords  and 
ladies  travelled  mostly  in  the  saddle.  General  com- 
merce counted  for  nothing,  and  what  little  survived  on 
land  was  hindered  or  destroyed  by  arbitrary  exactions 
and  continual  petty  wars. 

The  recovery  from  this  deplorable  condition  was 
slow  in  coming.  Not  only  the  roads  of  the  country 
but  even  the  streets  of  important  towns  were  often 
impassable  at  certain  seasons.  Even  in  the  twelfth 
century  the  only  main  roads  in  France  were  those 
originally  built  by  the  Romans.  Louis  XIV.  in  the 
latter  part  of  that  century  made,  it  is  true,  some  good 
roads  in  the  vicinity  of  Paris,  but  it  was  not  till  about 
1775  that  a  genuine  revival  took  place.  Under 
Napoleon  I.  road-building,  as  it  is  understood  to-day, 
had  a  great  development  both  in  France  and  in  the 
countries  which  he  conquered.  The  famous  road  over 


HISTORICAL.  3 

the  Simplon  Pass  from  Switzerland  into  Italy  was 
made  by  his  orders  in  1 800-6.  From  this  time  on 
the  progress  has  been  great  and  continuous ;  so  that 
to-day  all  Europe,  with  the  exception  of  Russia,  is 
covered  by  wagon-roads,  which  are  adapted  to  the  re- 
quirements of  each  district,  and  are  models  of  dura- 
bility and  excellence. 


ROADS  AND   PAVEMENTS  IN  FRANCE, 


A   PERFECT   WAGON-ROAD 

should  have  an  easy  grade,  a  surface  hard,  smooth, 
even,  and  slightly  convex  to  insure  prompt  and  per- 
fect drainage,  be  nearly  or  quite  impermeable  to  water, 
and  at  all  seasons  be,  as  nearly  as  practicable,  free 
from  mud  and  dust. 

Such  roads  are  to  be  found  in  the  best  of  our  city 
parks.  They  are  rather  costly  to  build,  and  are  kept 
in  perfect  order  only  by  constant  care.  Such  roads 
are,  however,  common  enough  in  all  parts  of  Europe, 
not  simply  as  park  roads  and  for  pleasure  driving 
merely,  but  as  the  high-roads  of  general  travel,  run- 
ning for  hundreds  of  miles  throughout  the  country, 
connecting  cities,  towns,  and  villages,  and  giving  easy 
communication  for  general  traffic.  Long  experience 
and  careful  study  have  convinced  the  various  govern- 
ments that  the  well-being  and  prosperity  of  all  parts 
of  the  country,  of  rich  and  poor  alike,  depend  in  great 
measure  upon  a  well-considered  system  of  highways, 
built  with  great  care  and  maintained  always  in  good 
order.  The  economy  to  each  community  of  a  good 
wagon-road,  whatever  may  be  its  cost,  is  no  longer  an 


UNIVERSITY 
A    PERFECT    WAGfrN^-i&Ap,  5 

open  question  in  countries  and  districts  where  small 
economies  of  all  kinds  are  matters  of  anxious  con- 
sideration. Thoroughness  of  construction  is  a  charac- 
teristic feature,  and  a  grade  once  established  and  a 
road  once  built  need  rarely  be  changed. 

The  saving  in  wear  and  tear  of  wagon  and  harness 
and  the  increased  loads  a  horse  can  haul  are  perfectly 
well  understood  and  recognized  by  all  who  have  prod- 
uce or  merchandise  to  carry  to  market.  Two  hun- 
dred years  ago  good  roads,  if  any  existed  then,  were 
built  for  the  convenience  and  pleasure  of  the  king  and 
his  nobles ;  to-day  they  are  built  to  serve  the  interests 
of  general  industry.  The  presence  or  absence  of  such 
means  of  communication  and  the  condition  in  which 
they  are  kept  are  justly  regarded  in  Europe  as  a  fair 
index  of  the  degree  of  civilization  of  the  community 
or  country. 

In  our  own  country  the  increased  demand,  within 
the  last  few  years,  for  improvement  of  the  highways, 
which  has  more  recently  taken  shape  in  state  legisla- 
tion, is  gratifying  evidence  of  a  growing  interest  in  the 
subject,  that  is  likely  to  lead  to  good  results. 

With  the  hope  of  aiding  the  cause  of  highway  im- 
provement the  writer  contributes  this  little  book, 
mainly  made  up  of  an  account  of  stone  roads  in 
France,  their  mode  of  construction  and  maintenance, 
and  embodying  to  some  extent  the  results  of  experi- 
ence of  some  of  the  best  French  engineers.  It  is 
chiefly  compiled  from  the  published  books  of  Monsieur 


O  ROADS  AND   PAVEMENTS  IN  FRANCE. 

A.  Debauve,*  Ingenieur  en  Chef  des  Fonts  et  Chaus- 
sees,  in  charge  of  the  Department  of  Oise,  and  from 
the  official  reports  of  the  Minister  of  Public  Works. 

As  a  matter  of  course,  the  methods  and  practice  of 
one  country  are  rarely  applicable  in  all  their  details  to 
another  country,  where  many  of  the  conditions  of 
population,  climate,  etc.,  are  quite  different.  At  the 
same  time  all  experience  teaches  something,  either  to 
imitate,  modify,  or  avoid ;  and  it  seems  probable  that 
we  may  learn  something  of  value  from  the  conclusions 
reached  by  the  highly  educated  and  able  engineers 
who,  one  after  another,  have  for  more  than  a  hundred 
years  had  charge  of  the  national  roads  of  France.  The 
best  and  most  economical  method  of  construction  and 
maintenance,  under  existing  conditions  of  climate  and 
population,  has  been  their  constant  aim ;  and  the  ex- 
cellent roads  of  France  to-day  are  the  best  evidence 
of  the  faithfulness  and  skill  of  the  French  engineers  in 
charge. 

The  improvement  of  our  own  roads,  which  so  many 
of  us  earnestly  desire,  cannot  be  too  carefully  and 
thoroughly  studied.  The  best  and  most  economical 
method  or  methods  of  construction  and  maintenance, 
the  adaptation  to  the  requirements  of  each  region  and 
of  each  special  case,  with  due  regard  to  the  amount  of 
present  and  future  travel  and  to  the  money  that  may 

*  Manuel  de  1'ingenieur  des  Fonts  et  Chaussees;  Paris,  1873. 
Instruction  Generate  pour  le  service  courant;  Paris,  1894.  Dic- 
tionnaire  Administratif  des  Travaux  Publics;  Paris,  1892. 


A    PERFECT    WAGON-ROAD.  7 

be  properly  spent  for  the  purpose,  the  nature  of  the 
material  to  be  used,  the  determination  of  grade  and 
width,  and,  above  all,  the  permanent  nature  of  the  work, 
are  fundamental  points  to  be  carefully  weighed  before 
decision.  No  detail  is  unimportant.  It  is  hoped  that, 
on  this  subject  at  least,  the  period  of  temporary  make- 
shifts is  over,  so  that  work  done,  however  incomplete, 
may  not  need  to  be  undone,  but  be  the  basis  of 
further  possible  improvement  in  the  future. 

We  are  no  longer  satisfied  with  the  common  dirt 
road,  which  served  a  useful  purpose  when  no  better 
was  to  be  had ;  and  yet  in  some  districts,  where  popu- 
lation is  sparse,  it  will  still  be  the  only  practicable  one. 
In  many  cases  it  may  doubtless  be  materially  improved 
at  no  greater  outlay  of  money  than  the  present  annual 
cost,  and  with  much  indirect  advantage  to  those  using 
it.  In  its  worst  form  and  under  the  most  unfavorable 
conditions  of  climate  and  soil  it  is  barely  endurable 
during  eight  or  nine  months,  and  is  often  nearly  im- 
passable for  two  or  three  months  of  the  year.  Its  like 
may  be  found  in  certain  parts  of  Russia,  where  the 
roads  give  easy  communication  only  during  four 
months  of  summer  and  four  of  winter. 

Between  the  two  wide  extremes  of  the  perfect  park 
road  before  mentioned  and  the  worst  mud  road  lie  all 
possible  degrees  of  goodness  and  badness. 

Assuming,  then,  that  the  object  is  to  get  the  best 
practicable  road  under  the  circumstances  in  each  case, 

the  various  points  to  be  considered,  whether  in  build- 

/«£-£-s£   !- 

f      ^  OF  THE? 

(UNIVERSITY 

\   CALIFORNIA. 


8  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

ing  a  new  road  upon  a  new  line,  or  in  improving  one 
already  built,  may  be  conveniently  grouped  under  the 
following  heads,  viz.  : 

1.  Grade. 

2.  Material. 

3.  Mode  of  Construction. 

4.  Maintenance. 

A  highway  is  a  permanent  work,  and  the  laying  out 
and  building  of  it  is  a  matter  of  corresponding  impor- 
tance. The  problem  should  be  studied  with  an  accu- 
rate survey  of  the  line  of  the  road  in  hand,  accom- 
panied by  full  specifications  and  close  estimates  of  the 
amount  of  each  part  and  kind  of  work  to  be  done. 
Such  preparatory  work  is  the  only  safe  basis  for 
determining  intelligently  the  several  points  at  issue. 
Without  it  the  whole  thing  is  a  matter  of  guesswork. 

Accuracy  is  always  economical  and  guesswork  costly 
and  wasteful.  A  shrewd  contractor's  guess  allows  a 
very  liberal  margin  to  cover  the  unknown.  It  is  the 
duty  of  the  engineer  to  define  accurately  the  conditions 
of  the  problem  and  eliminate  the  uncertainties,  and  if 
he  is  a  competent  one  his  services  are  many  times 
worth  his  cost. 

I.  GRADE. 

The  advantages  of  an  easy  grade  are  too  obvious 
for  discussion. 

The  standard  adopted  in  France  is : 


GRADE.  9 

National  roads,  not  exceeding  3  in  100 
Department  "        "  "         4  in  100 

Subordinate  "        "  "          5  in  100 

This  standard  is  adhered  to  where  practicable,  but 
obviously  the  rule  is  not  absolute,  and  is  very  often 
exceeded  of  necessity,  especially  in  a  mountainous  dis- 
trict, or  where  the  travel  is  too  light  to  justify  an 
excessive  expenditure  to  keep  the  grade  down  to 
standard. 

A  horse  may  be  easily  driven  at  a  trot  on  a  grade  of 
3  in  100,  whatever  its  length,  and  on  a  grade  of  4  in 
100  for  a  short  distance,  but  if  the  grade  is  steeper 
than  this  he  will  naturally  go  at  a  walk. 

Steep  grades  limit  so  greatly  the  load  a  horse  can 
haul  that,  if  the  road  is  much  used  by  heavily  loaded 
wagons,  the  greater  cost  of  the  longer  line,  with  easy 
grade,  would  often  be  sound  economy  in  the  long- 
run.  In  fact,  it  may  often  happen  that  the  extra  cost 
is  by  no  means  serious,  and  is  of  small  account,  in 
view  of  the  manifest  advantages  of  the  better  grade. 
This  point  should  be  most  carefully  studied  in  the 
laying  out  of  a  new  road.  The  errors  of  the  past  are 
hard  to  correct. 

The  idea  prevailed  at  one  time,  and  unhappily  was 
largely  acted  on,  that  the  main  road  between  impor- 
tant towns — such,  for  instance,  as  the  old  stage 
routes — should  be  a  straight  line,  going  up  and  down 
hill  across  the  country,  without  regard  to  the  in- 
equalities of  the  surface.  It  may  at  first  have  been 


10  ROADS  AND    PAVEMENTS  IN  FRANCE. 

the  most  direct  pathway  or  horse-track  through  the 
otherwise  trackless  forest,  or  it  may  be  a  legacy  of  the 
old  Roman  times,  when  the  marching  of  armies  was 
more  important  than  the  movement  of  heavy  loads  of 
produce  or  merchandise.  Whatever  its  origin,  the  re- 
sult to-day  is,  in  too  many  cases,  a  road  with  grades  that 
ought  to  be  modified  to  satisfy  modern  requirements. 
Moreover,  the  straight  line,  with  its  steep  ascents  and 
descents,  is  sometimes  not  even  the  shortest  in  actual 
distance.  But  even  if  it  be  somewhat  the  shortest, 
this,  its  only  advantage,  may  be  more  than  counter- 
balanced by  other  considerations.  It  not  unfrc- 
quently  is  the  case  that  a  road  winding  along  valleys  and 
around  the  hills  is  but  1/5  or  1/6  longer  than  the  direct 
road  over  the  hills.  It  must  also  be  remembered  that 
an  ascent  of  5  in  IO°  calls  for  an  expenditure  of  force 
in  hauling,  /;/  a  given  time,  three  times  as  great  as  if 
the  road  were  level ;  or,  if  the  force  expended  be  the 
same  in  both  cases,  then  the  time  of  ascent  must  be 
three  times  as  long.  Yet  a  grade  of  5  in  100  is  con- 
sidered moderate.  The  difference  is  still  more  strik- 
ing when  the  grade  is  6,  7,  or  10  in  100.  In  fact, 
all  the  arguments,  the  saving  of  time,  the  greater 
loads  that  can  be  hauled,  and  the  less  expense  of 
keeping  in  order,  are  in  favor  of  a  line  somewhat 
longer,  but  nearly  level  or  slightly  undulating,  as 
against  the  direct  line  over  the  hills.  The  straight 
line  is  only  an  abstract  idea  of  no  practical  utility. 
In  many  cases,  however,  there  is  evidently  ho 


MA  TERIAL.  1 1 

choice.  It  may  be  necessary  to  cross  a  range  of  hills 
that  are  not  cut  by  cross  valleys,  or  the  road  must  be 
carried  over  the  hill  to  serve  the  village  on  the  sum- 
mit, though  even  here  the  height  should  be  sur- 
mounted by  a  winding  road  with  easy  grade.  But 
where  there  is  no  such  determining  reason  every  con- 
sideration of  economy  and  public  convenience  favors 
the  longer  line,  winding  with  easy  grades  along  the 
valley. 

An  absolutely  uniform  grade  is  theoretically  the 
best  for  hauling,  and  on  railways  with  steam  or  electric 
power  it  is  practically  the  best,  but  where  horses  are 
used  it  is  far  from  having  the  same  advantages.  Ex- 
perience seems  to  show  that  nothing  fatigues  a  horse 
so  much  as  a  steady  pull  up  a  long  uniform  grade, 
and  that  it  is  often  better  to  vary  the  strain  on  the 
collar  by  varying  the  grades.  An  alternation  of 
slightly  ascending  and  descending  grades  is  preferable 
to  a  dead  level,  not  only  for  the  comfort  of  the  horse, 
but  to  secure  more  perfect  drainage  of  the  roadway. 

II.    MATERIAL. 

A  clay  soil  gives,  perhaps,  the  worst  possible  road. 
During  a  part  of  the  year,  when  hard,  dry,  and 
smooth,  the  road  seems  to  answer  all  the  essential 
requirements,  but  at  some  seasons  it  becomes  well- 
nigh  impassable  for  heavily  loaded  wagons,  and  is 
endurable  only  when,  in  a  sparsely  settled  region,  the 


12  ROADS  AND   PAVEMENTS  IN   FRANCE. 

community  is  too  poor  to  afford  the  cost  of  better 
material  brought  from  a  distance.  The  wooden  plank- 
road,  adopted  in  some  parts  of  the  West,  was  a  tem- 
porary remedy. 

Gravel,  under  certain  conditions  and  when  properly 
used,  answers  most  of  the  requirements.  All  which 
passes  under  that  name,  however,  is  not  equally  good. 
For  this  purpose  it  should  be  as  free  as  possible  from 
clay  or  marl.  In  regions  where  it  is  abundant  it  is 
the  material  naturally  used  on  all  country  roads,  and 
nothing  will  replace  it  till  the  increase  of  population, 
and  consequent  increase  of  use,  demand  a  harder  and 
more  durable  substitute.  A  gravel  road,  like  every- 
thing else,  wears  out  with  use,  and,  in  proportion  to 
the  amount  of  travel,  requires  more  or  less  frequent 
renewal  with  fresh  material-*  What  has  been  washed 
off  of  it  into  the  ditches  should  never  be  scraped  back 
on  to  its  surface, 

Broken  Stone. 

This,  beyond  question,  is  the  best  material.  Its 
cost,  however,  and  the  care  needed  for  its  proper  use 
limit  its  general  adoption  to  cases  where  the  amount 
of  travel  or  other  special  reason  justifies  a  large  ex- 
penditure of  money. 

The  choice  of  the  kind  of  rock  to  be  used  is  impor- 
tant, though  in  the  majority  of  cases  there  is  practi- 
cally but  little  choice,  and  the  rock  nearest  at  hand 


JHXVERSil 

»  13 


must  be  the  one  used.  The  hardest  and  toughest  is 
the  best,  since  roads  made  of  it  are  more  durable, 
have  a  harder  surface,  diminish  the  resistance  to  be 
overcome  in  hauling,  and  with  an  equal  amount  of 
travel  are  less  worn,  and  consequently  are  more  easily 
and  cheaply  kept  in  order. 

The  choice  most  frequently  lies  between  an  inferior 
and  cheaper  rock  close  at  hand,  and  a  better  but  more 
costly  one  brought  from  a  distance.  The  better  and 
more  expensive  rock  may  prove  more  economical  in  the 
long-run,  but  the  cost  and  conditions  in  each  case 
must  decide  the  question.  The  relative  quality  of  the 
different  rocks  available  —  that  is,  their  hardness,  tough- 
ness, mode  of  fracture,  and  fitness  for  this  special  pur- 
pose —  should  be  first  determined  by  careful  tests  in  each 
instance  without  regard  to  the  name  of  the  rock,  since 
rocks  having  the  same  general  name  vary  very  mate- 
rially in  fitness  for  this  use.  The  better  the  quality, 
the  less  proportionally  is  the  wear,  and  the  wear  is 
regarded  as  being  in  proportion  to  the  amount  of 
travel. 

Hardness,  though  most  valuable,  is  not  the  only 
thing,  for  the  rock  may  be  hard  and  tough  and  resist- 
ant, or  it  may  be  hard  and  brittle  and  splinter  easily 
under  the  blows  of  heavy  wheels,  so  that  a  somewhat 
softer  but  tougher  rock  may  prove  in  practice  the  more 
advantageous. 

In  France  a  scale  of  quality  from  o  to  20  has  been 
adopted,  in  which  20  stands  for  the  best. 


14  ROADS  AND   PAVEMENTS   IN  FRANCE. 

*  Following  is  a  list  of  most  of  the  varieties  of  rock 
used,  with  the  quality  of  each  kind: 

Quality. 

Porphyry varying  from  10  to  20 

Trap "  "  16  "  20 

Basalt "  "  10  "  19 

Quartzite "  "  H   "   19 

Gres  quartzose "  "  10  "  20 

Flint "  "  8  "   19 

Quartz, "  "  10  "   18 

Serpentine "  '•  12  "    18 

Melaphyr   "  "  16  "   17 

Diorite "  "  13  "   17 

Limestone "  "  5  "   17 

Gneiss "  «'  5  "   17 

Granite ««  4<  8  "   16 

Millstone  grit "  "  6  u   16 

Amphibolite "  4<  11   "   15 

Schist "  4<  3  «•   15 

Mica  schist   "  ««  •  6  "   13 

Pudding-stone "  "  4"     8 

The  wide  variation  in  the  quality  of  rocks  classed  un- 
der the  same  name  is  noteworthy  and  instructive,  and 
the  list  is  given  here  mainly  to  show  it,  for  the  fact  is  that 
flint  and  limestone  are  by  far  the  most  commonly  used. 

The  quality  taken  in  connection  with  the  cost  of  the 
broken  stone  delivered  on  the  road  must  evidently 
determine  the  economy  of  using  one  rock  or  another. 

*  Mini^t^re  des  Travaux  Publics.     Routes  Nationales,  1893. 


MATERIAL. 


Thus  it  would  probably  be  economy  to  use  trap  of 
quality  20  in  preference  to  limestone  of  quality  8,  even 
if  the  cost  of  the  former  be  double  that  of  the  latter. 

In  the  year  1893  there  were  used  in  the  repair  of 
the  22,000  miles  of  "Routes  Nationales "  about 
1,702,000  cubic  yards  of  stone.  The  general  average 
quality  was  10.85.  One  fifth  of  the  whole  was  of 
quality  15  to  20,  and  one  fourth  was  of  quality  7  and 
below.  Evidently  it  was  thought  better  economy  to  use 
the  inferior  and  cheaper  stone  near  at  hand  rather  than 
the  better  and  more  costly  from  a  distance. 

As  an  instance,  take  the  Department  of  Oise.  They 
use — 

1 .  Flints,  collected  from  the  fields  and  quarries,  the 
quality  of  which  varies  between  8  and  13,  averaging  1 1. 

2.  Limestone  from  quarries;  quality,  8  to  9. 

3.  Millstone  grit,    compact;    quality,    13    and    up- 
wards. 

4.  Porphyry;  quality  20. 

In  the  year  1893  there  were  used  for  repair  of  250 
miles  of  road  in  this  Department,  as  follows : 


Kind. 

Quality. 

guantity, 
ib.  Yds. 

Coat  of  Stone  per 
Cub.  Yd. 

Average. 

Limestone  

$0    6  to  $i    8 

$O  96 

Flint 

II    12 

i  ^  6^  ^ 

o  83  to     i  48 

Millstone  Grit           .  . 

16 

)       .       ( 

I  Q1  to      2  7^ 

Porphyry        

20. 

f  3,892] 

2  ii  to     3  54 

12.96 

17,970 

1.47* 

The  average  travel  was  227.8  units  in  the  24  hours. 


1 6  ROADS  AND    PAVEMENTS   IN  FRANCE. 

The  quantity  used  was  72  cub.  yds.  per  mile  or 
3 1 .60  cub.  yds.  per  mile  and  100  units.  (See  page  65.) 

The  stone  of  best  quality  and  highest  price  was 
used  on  roads  in  and  about  the  large  towns,  where  the 
travel  is  heavy.  The  flint  of  medium  quality  and  low 
price  was  used  on  the  greater  part  of  the  roads. 

<_ 
Preparation  of  the  Material. 

The  cleanness  of  the  stone  is  important.  Soil,  loam, 
and  even  gravel  or  sand  incorporated  in  the  body  of 
a  stone  roadway  are  injurious  to  its  solidity.  Other 
things  being  equal,  the  roadway  is  so  much  the  better 
the  less  fine  material  it  contains;  hence  the  need  of 
care  to  have  the  stone  clean.  That  broken  by  the 
crusher  or  by  hand  will  naturally  be  free  from,  foreign 
matter,  but  stones  gathered  in  the  fields  and  used  un- 
broken will  nearly  always  have  more  or  less  soil  or  clay 
adhering  to  them. 

The  size  to  which  the  rock  should  be  broken  depends 
on  its  hardness  and  the  special  use  intended.  Pieces 
3  to  4  inches  in  diameter  are  suited  for  the  body  of  a 
new  road,  where  a  heavy  stone  roller  is  used,  more 
especially  if  the  rock  is  no  harder  than  limestone ;  but 
if  it  be  much  harder,  like  trap,  the  standard  size  both 
for  new  work  and  repair  is  2J-  inches  in  diameter. 
Where  a  heavy  steam-roller  is  not  used,  it  may  well 
be  i  J  to  2j  inches.  Absolute  uniformity  and  regularity 
of  dimensions  is  practically  impossible,  desirable  as  it  is ; 


CONS  TR  UCTION.  1 7 

but  any  considerable  inequality  in  size  is  objectionable, 
as  it  tends  to  cause  unequal  wear,  and  in  time  makes 
the  surface  rough  with  protuberances.  This  is  espe- 
cially true  when  the  harder  rock  is  used.  Pieces  ap- 
proximately cubical  in  shape,  with  sharp  edges,  are 
better  compacted  under  the  roller  and  form  a  more 
solid  roadway. 

III.   CONSTRUCTION. 

The  simplest  method  of  making  a  common  dirt  road 
is  evidently  to  plough  a  few  furrows  on  each  side, 
where  the  ditches  are  to  be,  and  scrape  the  material 
toward  the  centre,  rounding  it  up  enough  to  cause 
the  rainfall  to  drain  off  as  promptly  as  possible. 
This  is  one  degree  better  than  no  road  at  all,  and  in  a 
new  country  does  well  enough  when  dry,  but  during 
part  of  the  year  the  depth  of  mud  on  it  depends  mainly 
on  the  richness  or  the  clayey  nature  of  the  soil  com- 
posing it.  The  richer  the  soil  the  worse  the  road. 

If  the  soil  happens  to  be  gravelly,  and  a  thickness, 
say  of  3  to  4  inches,  of  gravel  be  put  upon  the  road,  the 
result  is  quite  different.  But  even  a  gravel  road  often 
leaves  much  to  be  desired.  The  drainage  is  almost 
always  defective,  no  matter  how  high  it  may  be  rounded 
up  in  the  middle,  and  in  fact  the  more  it  is  crowned, 
if  the  road  be  narrow,  the  worse  it  often  becomes ;  for 
the  inevitable  tendency  to  form  a  single  track  along 
the  middle  is  increased,  and  the  deeper  the  wheel- 


1 8  ROADS  AND   PAVEMENTS  IN  FRANCE. 

tracks  the  more  they  hold  the  water  and  prevent 
proper  drainage.  A  very  moderate  amount  of  atten- 
tion might  greatly  improve  such  a  road.  The  con- 
struction of  an  ordinary  gravel  road  is  shown  in  Fig. 
I.  To  keep  such  a  road  in  perfect  condition  requires 
considerable  care.  The  frequency  of  renewal  with 
fresh  gravel  and  the  quantity  required  must  depend 
upon  the  amount  of  travel  and  consequent  wear.  The 


FIG.  i. — GRAVEL  ROAD. 

vicious  method  of  repair,  so  commonly  used,  which 
consists  in  scraping  every  spring  from  the  ditches  the 
fine  mud  which  has  been  washed  off  from  the  road, 
and  in  putting  it  back  upon  the  road  tends  to  ruin 
what  might  otherwise  be  a  very  tolerable  roadway. 
Repairs  should  always  be  made  with  fresh  gravel. 

Stone  Roads. 

All  of  the  methods  employed  in  the  building  of  stone 
roads  have  one  essential  characteristic  in  common,  viz.  : 
The  upper  layer  of  the  roadway  is  made  up  of  stone 
broken  into  small  pieces  and  compacted  so  as  to  form  a 
solid  mass.  This  layer  must  be  built  and  maintained  in 
such  manner  that  wagon-wheels  shall,  under  no  circum- 


ROADS    WITH  FOUNDATION.  1 9 

stances,  cut  through  it  and  penetrate  the  stone  founda- 
tion, if  the  road  is  built  with  one,  or  the  ground  below, 
if  the  layer  of  broken  stone  rests  immediately  on  the 
earth. 

The  old  Roman  roads  were,  according  to  modern 
ideas,  unnecessarily  thick  and  solid.  Enduring  as  they 
were,  the  great  cost  of  such  thick  masses  of  masonry 
would  not  be  borne  to-day.  The  modern  road  has 
either  no  stone  foundation  at  all  or  one  of  only 
moderate  thickness.  In  France  the  tendency  has  been 
to  do  away  with  the  foundation,  and  to  reduce  the 
thickness  of  the  upper  layer,  making  it  only  so  thick 
as  is  necessary  to  give  sufficient  resistance  ;  in  short,  to 
build  less  costly  roadways  and  to  maintain  them  in 
proper  condition  by  constant  care. 

The  various  methods  employed  resolve  themselves 
into  two  general  classes :  the  one,  roads  with  stone 
foundation ;  the  other,  roads  without  it.  These  have 
been  more  or  less  modified  by  the  whim  of  the  engi- 
neer, or  by  unusual  requirements  in  special  cases. 

Roads  with  Foundation. 

As  early  as  1764  Tresaguet,  a  French  engineer,  in- 
troduced great  improvements  in  the  mode  of  construc- 
tion, which  ten  years  later  were  generally  adopted  in 
France.  Such  stone  roads  as  there  were  at  that  time 
were  1 8  feet  wide,  and  had  generally  a  thickness  of  18 
to  22  inches  in  the  middle  and  12  to  16  inches  on  the 
edges.  Tresaguet  considered  this  thickness  excessive, 


UNIVERSIT 


20  ROADS  AND    PA  VEMENTS  IN  FRANCE. 

and  reduced  it  to  10  inches,  but  made  it  uniform  for 
the  whole  width  of  the  roadway.  The  earth  was  ex- 
cavated to  the  requisite  depth  for  the  whole  width  of 
the  proposed  roadway,  thus  forming  a  broad  shallow 
trench,  which  was  to  receive  the  stone.  Under  the 
earlier  system  the  bottom  of  this  trench  was  horizontal, 
but  Tresaguet  gave  it  the  same  convexity  that  the 
surface  of  the  roadway  would  have  when  finished.  On 
this  smoothly  dressed  bed,  sloping  from  the  centre  to 
the  edges,  the  first  layer  of  somewhat  large  stones  was 
carefully  laid  by  hand  on  their  edges,  and  as  compactly 
as  possible;  it  formed  thus  a  kind  of  rough  pavement. 
On  top  of  this  successive  layers  of  somewhat  smaller 
stones  were  laid,  also  by  hand,  projecting  points 
broken  off  with  a  sledge  and  thoroughly  pounded  till 
the  mass  was  solid,  care  being  taken  to  fill  up  the 
spaces  between  the  stones.  This  constituted  the 
foundation.  Finally,  the  top  layer,  three  inches  thick 
of  stone  broken  to  about  the  size  of  a  walnut,  was 
spread  uniformly  over  the  surface.  Tresaguet's  sys- 
tem, more  or  less  slightly  modified,  was  the  one  used 
almost  exclusively  in  France  until  about  1820,  and 
under  it  were  built  all  of  the  roads  now  classified  as 
"roads  with  foundation."  Of  the  22,000  miles  of 
Routes  Nationales  in  France,  only  about  9000 
miles,  however,  are  roads  with  foundation.  Some  of 
the  roads  built  under  Tresaguet's  system  had,  however, 
a  thickness  of  16  to  20  inches,  an  additional  layer  of 
stones,  laid  flat,  being  placed  at  the  bottom,  and  on 


TELFORD'S   SYSTEM.  21 

top  of  this  layer  stones  on  their  edge,  and  so  on  to  the 
surface  as  above  described.  This  additional  layer  was 
required  only  when  the  ground  was  not  thought  suffi- 
ciently solid. 

Telford's  System. 

This  is  a  modification  of  Tre"saguet's  system,  intro- 
duced into  England  by  Telford,  an  English  engineer, 
about  1820,  and  received  with  much  favor.  The 
practical  identity  in  principle  of  the  two  systems  is 
such  that  it  is  unnecessary  to  describe  in  detail  the 
whole  construction.  From  the  specifications  for  build- 
ing a  part  of  the  Holyhead  road  we  may  learn  Tel- 
ford's  early  practice.  The  bed  of  the  trench  is  hori- 
zontal, and  not  rounding.  The  larger  stones  for  the 
foundation  to  be  placed  in  the  middle  of  the  road  are 
9  inches  deep,  and  at  9  feet  from  the  centre  5  inches. 
They  are  to  be  placed  with  their  longest  edge  perpen- 
dicular to  the  axis  of  the  roadway,  and  their  width  at 
the  top  is  in  no  case  to  exceed  4  inches.  All  of  the 
projections  of  the  upper  surface  are  to  be  broken  off, 
and  the  interstices  between  the  stones  filled  with  small 
fragments  well  rammed  in.  This  foundation  is  then  a 
rough  pavement  having  a  convexity  of  1/60.  This  is  to 
be  covered  with  a  layer,  6  inches  thick,  of  hard  stone, 
so  broken  that  the  largest  piece  in  its  longest  dimen- 
sion can  pass  through  a  ring  of  2\  inches  interior  di- 
ameter. Four  inches  of  this  layer  are  to  be  spread 
first,  and  after  this  sublayer  has  become  quite  solid 


ROADS  AND    PA  VEMENTS  IN  FRANCE. 

and  compact  by  travel  the  two  remaining  inches  are 
spread  evenly  over  it.  Finally,  the  whole  surface  is  to 
be  covered  with  a  coating,  i£  inches  thick,  of  good 
gravel  free  from  earth  or  clay. 

Since  that  time  the  Telford  method  has  been  more 
or  less  modified,  but  the  characteristic  foundation  of 
larger  unbroken  stones,  supporting  a  thinner  surface 
layer  of  small  broken  stone,  is  essentially  unchanged. 

This  method  of  construction,  as  oiten  employed,  is 
shown  in  Fig.  2. 


*^S'£<LZ&Z&Z{//4W////^ 


FIG.  2. — TELFORD  ROAD. 

It  will  be  noticed  that  the  bottom  layer  of  large 
stones,  which  forms  the  foundation,  rests  upon  a  hori- 
zontal bed  of  natural  earth.  The  better  construction 
is  to  give  to  the  surface  of  this  bed  the  same  convexity 
or  crowning  as  that  of  the  finished  road,  thereby  in- 
suring better  subdrainage  of  any  water  that  may  find 
its  way  to  that  surface.  The  stone  layer  is  conse- 
quently of  uniform  thickness  the  whole  width  of  the 
roadway. 

The  roads  built  in  Essex  County,  N.  J.,  by  Mr. 
James  Owen,*C.E.,  are  examples  of  this  system.  The 

*  Address  on  Highway  Construction  in  New  Jersey.      By  James 
Owen,  C.E.      1893. 


ROADS    WITHOUT  FOUNDATION.  2$ 

earlier  roads  he  built  12  inches  thick,  that  is,  8  inches 
of  foundation  and  4  inches  of  broken  stone.  Subse- 
quent experience  has  led  him  to  recommend  for  all 
ordinary  highway  purposes  a  total  thickness  of  8 
inches,  that  is,  5  inches  of  foundation  and  3  inches  of 
stone  broken  to  the  size  of  I  £  to  2  inches  in  diameter. 

A  thin  layer  of  loam  or  clay  is  sometimes  spread  on 
top  of  the  foundation  to  fill  the  spaces  between  the 
stones  and  give  an  even  surface  to  receive  the  top 
layer  of  small  stones.  After  the  small  stones  have 
been  brought  to  a  somewhat  even  surface  under  a  two- 
ton  roller  a  thin  coating  of  loam  is  spread  over  them. 

Other  engineers  disapprove  of  the  addition  of  loam 
or  clay  into  the  body  of  the  roadway  or  upon  the  sur- 
face, believing  it  to  be  a  positive  injury  to  the  solidity 
of  the  road.  They  advocate  a  heavier  roller,  as  a 
means  of  compacting  the  stone  and  of  making  the 
roadway  more  enduring. 

Roads  without  Foundation. 

These  are  all  made  on  the  Macadam  system  more 
or  less  modified.  This  system  consists  essentially  in 
doing  away  with  a  stone  foundation  of  any  kind,  and 
in  replacing  the  two  or  three  layers  of  the  older  system 
by  a  single  layer  6  to  10  inches  thick,  rarely  less,  of 
small  broken  stone  as  nearly  as  practicable  uniform  in 
size,  which  layer  shall  be  impermeable  to  water. 

The  grea-t  road  over  the  Simplon  Pass  from  Switzer- 


24  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

land  into  Italy,  built  by  French  engineers  under  the 
orders  of  Napoleon  I.,  was  perhaps  the  first  road  of  im- 
portance built  without  a  specially  laid  stone  founda- 
tion. The  perfect  solidity  of  the  rocky  bed  rendered 
such  a  foundation  unnecessary.  The  roadway  was 
accordingly  composed  of  small  broken  stone  from  bot- 
tom to  top  without  distinction  of  layers. 

Macadam  in  England  in  1816  appeared  with  his 
method,  and  made  such  great  improvement  in  the  roads 
put  under  his  care  that  his  system  was  generally 
adopted  in  England,  and  for  several  years  had  no  rival 
till  Telford  and  the  advocates  of  roads  with  founda- 
tion gained  a  share  of  popular  favor. 

Subsequently  Macadam's  system  was  introduced 
into  France,  and  gave  such  satisfactory  results  that  it 
became  thoroughly  established  there,  so  that  for  many 
years  it  has  been  used  exclusively  on  all  of  the  public 
roads.  All  of  Macadam's  ideas  were  not  accepted, 
but  the  essential  principles  have  been  applied  in  the 
construction  of  nearly  all  the  modern  French  roads. 

The  ordinary  method  of  construction  of  a  macadam 
road  is  shown  in  Fig.  3. 


FIG.  3. — MACADAM  ROAD. 

The  thickness  of  the  layer  of  broken   stone  is  here 
given   as    10   inches.      It  is  sometimes,  though  rarely, 


lUNIVEH^ 
MACADAM*S*&YSS&£&^1>--  25 

more,  and  is  oftener  less,  especially  where  the 
natural  foundation  is  exceptionally  dry  and  solid. 
The  size  of  the  broken  stone  is  very  generally  2-J 
inches,  but  in  some  cases  the  lower  part  of  the  layer 
may  be  made  of  stones  3  to  4  inches  in  diameter  and 
the  upper  half  2^  to  ij  inches  in  diameter. 

Thickness. — A  stone  roadway  may  be  solid  without 
being  very  thick.  The  essential  condition  is  that  it 
shall  form  a  compact  and  impermeable  mass,  com- 
pletely protecting  the  ground  below  from  the  effects 
of  moisture.  The  natural  earth,  when  perfectly  dry, 
will  resist  sufficiently  well  the  heaviest  loads.  It  is 
quite  possible,  using  broken  stone  2  inches  and  less  in 
diameter,  to  make  a  solid  roadway  that,  when  com- 
pacted, shall  be  only  four  inches  thick.  There  are 
many  old  roads  still  in  good  condition,  which  have 
been  found  on  examination  to  have  a  thickness  not 
exceeding  four  inches.  But  such  a  road  could  hardly 
be  durable  except  under  the  most  favorable  conditions 
of  soil  and  climate.  It  might  answer,  if  the  ground 
beneath  were  hard,  gravelly,  and  naturally  dry  and  the 
travel  light,  but  in  the  great  majority  of  cases  it  would 
not  resist  the  frosts  of  many  winters.  A  thickness  of 
less  than  6  inches  is  not  advisable ;  that  of  8  inches  is 
much  better.  This  means  the  thickness  of  the  finished 
road  after  the  stone,  loosely  spread,  has  become  com- 
pacted and  solidified  by  persistent  rolling  or  travel. 
Experience  seems  to  show  that  the  harder  the  stone 
the  less  the  thickness  required. 


26  ROADS  AND    PAVEMENTS   IN  FRANCE. 

In  this  connection  the  official  *  report  on  the  pres- 
ent condition  of  the  Routes  Nationales  of  France 
may  be  of  interest. 

The  22,000  miles  of  Routes  Nationales  are  peri- 
odically examined  with  great  care  in  order  to  ascer- 
tain the  actual  thickness  of  the  stone  layer,  and  to 
determine  whether  the  roadway  has  been  fully  main- 
tained by  restoring  to  it  annually  fresh  material  to 
replace  that  lost  by  wear,  or  whether  it  has  been 
allowed  to  deteriorate.  Tests  were  accordingly  made 
in  1865,  1874,  1886,  and  1891,  and  they  were  most 
thorough. 

At  intervals  of  656  feet  (2OOm)  along  the  road  a 
trench  is  cut,  at  right  angles  with  the  axis  of  the  road, 
from  the  middle  to  the  outer  edge  of  the  stone  layer. 
This  trench  is  about  20  inches  (om.5o)  wide,  and  is 
dug  with  the  pick  down  to  the  earth  below,  or  to  the 
stone  foundation,  if  there  is  one,  without  penetrating 
either,  and  the  contents  removed.  The  width  and 
depth  of  this  trench  are  then  accurately  measured.  A 
perfect  section  is  thus  made  of  one  half  of  the  road- 
way. These  trenches  are  cut  alternately  on  the  right 
and  left  sides  of  the  axis  of  the  road,  so  as  to  give 
sections  of  the  whole  width  without  at  the  same  time 
interfering  with  travel.  The  general  average  of  nearly 
500,000  such  tests,  made  in  1891,  showed  a  thickness 
of  5J-  inches  (om.i3i).  The  average  thickness  of  the 

*  Ministerc  des  Travaux  Publics.  Routes  Nationales.  Bondages 
des  Chauss6es  en  1891. 


THICKNESS   OF  STONE, 


layer  of  broken  stone  of  roads  with  stone  foundation 
was  4^  inches  (om.iO7)  above  the  foundation,  and  on 
roads  without  foundation  5$  inches  (o111. 148).  This 
general  average,  however,  by  no  means  represents  a 
uniform  thickness  throughout  the  country.  Thus  in 
different  regions,  and  for  reasons  that  are  not  apparent, 
it  ranges  on  roads  without  foundation  from  3j-  in. 
(o'".079)  to  i of  in.  (om.27o),  and  on  roads  with  foun- 
dation from  2\  in.  (ol".o64)  to  8J  in.  (olll.2i8). 

The  following  table  shows  by  percentages  the  rela- 
tive number  of  miles  of  the  different  thicknesses: 


Witth-      With 

Thickness  of  Stone 

Layer. 

Fn»n         Foun- 

S&  d;uion- 

Total 
Per 

p'r       Per 

cent. 

cent.       cent' 

Less  than 

2  inches   (o'n  05) 

6  •  Q  j.    16  •  80 

Between  2 

in.  (oin.o5)  and 

4  in.  (otn.ioi  

26.13  38.29 

31.06 

4 

"    (o'Mo)  and 

6    "  (o'M5)  

27.58  26.05 

26.96 

6 

"    (om.i5)  and 

8     "  (o'n.2o)  

20.19    n-43 

16.63 

8 

"    (o'".2o)  and   i 

2    "  (om.3o)  

15.12      6.  ii 

11.47 

More  than 

12  in    (om  30)  . 

401         T    o  o 

2r\/t 

•U4        I-,)* 

•94 

IOO.OO  IOO.OO 

IOO.OO 

From  which  it  appears  that  two  fifths  of  the  total 
length  of  the  Routes.  Nationals  have  a  thickness 
less  than  4  inches,  and  4  inches  is  the  limit  below 
which  it  is  thought  unsafe  to  go.  One  eighth  only 
have  a  thickness  exceeding  8  inches. 

A  comparison  with  the  tests  made  in  1886  shows 
that  the  general  average  thickness  on  the  22,000  miles 


28  ROADS  AND   PA  VEMENTS  IN  PRANCE. 

was  only  5/32  inch  less  in  1891  than  in  1886.  This 
seemingly  trifling  difference,  however,  represents  a 
net  loss  of  about  730,000  cubic  yards  of  material  from 
the  surface  of  the  roads,  and  would  seem  to  indicate 
that  that  amount  of  broken  stone  was  needed  to  re- 
store the  roads  to  the  condition  they  were  in  five 
years  before. 

As  to  what  may  be  the  condition,  in  this  respect, 
of  the  300,000  miles  of  stone  road  variously  classed  as 
departmental,  communal,  etc.,  the  writer  is  unable  to 
say,  as  there  are  no  official  reports  published  or  read- 
ily accessible ;  but  it  is  assumed  that  they  have  been 
built  in  the  same  general  manner  and  on  the  same 
principles  as  the  Routes  Nationales.  It  is  certain, 
however,  that  many  of  them  lack  the  perfection  which 
characterizes  the  latter,  and  are  not  maintained  with 
the  same  care. 

Binding  Material. 

The  stone  layer,  6  to  9  inches  thick,  which  forms 
the  solid  roadway,  inevitably  contains  a  certain  per- 
centage of  fine  material  intermixed  with  the  broken 
stone,  even  when  none  is  intentionally  added  while  the 
road  is  being  built.  This,  in  an  old  roadway,  is  rarely 
less  than  33  per  cent,  and  is  often  as  much  as  50  per 
cent  of  the  whole  mass.  In  the  best  roads  this  so- 
called  binding  material  is  formed  in  part  by  the  crush- 
ing of  the  stones  or  their  grinding  one  against  another 


BINDING   MAl^ERIAL.  2$ 

under  the  heavy  steam-roller  when  the  road  is  first 
built,  and  in  part  by  subsequent  travel. 

In  some  districts  the  practice  has  prevailed,  and  is 
still  adhered  to,  of  mixing  a  certain  percentage  of  fine 
gravel  as  binding  material  with  the  broken  stone  at 
the  outset.  In  support  of  this  practice  it  is  urged 
that  a  good  roadway  always  contains  at  least  33  per 
cent  of  fine  material  and  that  it  is  better  to  mix  this, 
at  the  outset,  with  the  stone,  rather  than  let  it  be 
formed  at  the  expense  of  the  more  costly  stone. 

This  is,  however,  believed  to  be  a  mistake,  and  the 
theory  on  which  it  rests  a  false  one.  Doubtless  a 
road  containing  33  per  cent  of  binding  material  may 
be  a  good  one,  but  it  would  be  a  better  one  if  it  con- 
tained less.  Some  of  the  best  engineers  consider  the 
point  now  well  settled,  that,  other  things  being  equal, 
a  roadway  is  so  much  the  better  the  less  fine  material 
it  contains. 

It  is  true  that,  where  no  heavy  roller  can  be  had, 
the  mixing  of  a  moderate  quantity  of  gravel  with  the 
broken  stones  may  seem  desirable  in  order  to  bind 
them  the  more  quickly,  but  it  is  equally  true  that  this 
factitious  solidity  must  always  be  at  the  expense  of 
the  ultimate  durability  of  the  road.  Hence  no  bind- 
ing material  should  be  mixed  with  the  stone,  but  the 
latter  should  be  kept  perfectly  clean  and  free  from  all 
foreign  matter  whatever.  The  passage  of  a  lo-ton 
steam-roller  40  or  50  times  over  a  given  point  renders 
all  binding  material  superfluous,  and  compacts  the 


30  ROADS  AND   PAVEMENTS  IN  FRANCE. 

stone  so  thoroughly  that  it  becomes  a  mass  nearly  as 
solid  as  the  rock  itself. 

It  is  interesting  to  note  that  prior  to  1830  neither 
steam  nor  horse-roller  was  used,  ordinary  travel  being 
forced  to  gradually  compact  the  loose  stones.  About 
that  year  it  was  tried  in  England,  and  a  few  years 
later  was  introduced  into  France. 

When,  however,  the  broken  stone  has  been  thor- 
oughly compacted  under  the  heavy  roller,  and  not  till 
then,  a  layer  of  screened  gravel,  free  from  clay,  1/3 
inch  thick  should  be  spread  over  the  surface  to  fill  up 
the  small  interstices  that  may  still  be  left  at  the  top. 
Clay  or  loam  has  sometimes  been  used  instead  of 
gravel  or  sand.  It  makes  an  excellent  surface  at  cer- 
tain seasons,  but  in  wet  weather  it  becomes  muddy 
and  in  dry  weather  dusty.  It  is  especially  objec- 
tionable when  subjected  to  alternate  freezing  and 
thawing. 

Reduction  of  Bulk. 

Stones  broken  so  as  to  pass  through  a  ring  2-J  inches 
in  diameter  occupy,  when  roughly  spread,  about  55 
per  cent  of  the  thickness  of  the  layer,  leaving  45  per 
cent  of  vacant  spaces  between  them.  A  layer  there- 
fore 6  inches  thick  would  have  3.3  inches  of  stone  and 
2.7  inches  of  spaces.  When  completely  solidified  by 
persistent  rolling  with  a  heavy  roller  the  6-inch  layer 
would  be  reduced  to  a  thickness  of  less  than  4  inches. 


CONVEXITY  OF  ROAD.  31 

Convexity. 

The  convexity,  that  is,  the  rounding  up  or  crown- 
ing, of  the  roadway  may  be  stated  either  in  its  rela- 
tion to  the  width  of  the  roadway  or  as  showing  the 
slope  from  the  centre  to  the  edges:  thus  1/18  means 
that  a  roadway  18  feet  wide  is  i  foot  higher  in  the 
centre  than  at  the  edges,  which  is  the  same  as  saying 
that  the  slope  from  the  centre  to  the  edges  is  4  inches 
to  the  yard.  The  following  table  may  be  convenient 
for  reference  : 

i/iS  =  4  inches  to  the  yard. 
1/24  =3      "        "     "      " 

1/30  =  2|  "    "   "    " 

1/36  =  2  " 

1/42  :rr  if  " 

1/48  =  l|  " 

1/54  =  ij  " 
1/60  =  i-l  '* 

1/66  =   ly'j-  "       "    "      « 

1/72  =  i  ««     "      " 

1/84=    f    "       ((     "      << 
1/96=    f    "       "     " 

The  convexity  given  to  the  old  roadways  was  ex- 
cessive, the  cross-section  showing  a  slope  from  the 
centre  of  2j,  3,  and  even  4  inches  to  the  yard.  The 
evident  purpose  was  to  promote  good  drainage  and 
thereby  insure  the  solidity  of  the  roadway  ;  but  the 


li  "  tl 

«  u  t< 

"  "  " 

"  " 


32  ROADS  A ND   PA  YEMEN TS  IN  FRA NCE. 

fact  is  that  water  will  drain  readily  from  a  surface 
that  may  have  but  very  slight  inclination,  provided 
the  surface  is  even.  The  important  point  is  to  keep 
the  surface  even,  and  to  prevent  the  formation  not 
only  of  ruts,  but  even  of  permanent  tracks,  since  these 
hold  the  water  and  prevent  its  proper  drainage,  how- 
ever great  may  be  the  convexity  of  the  roadway. 
The  more  rounded  the  surface  the  greater  is  the 
tendency  of  travel  to  keep  to  the  middle,  and  a  track 
once  begun  is  worn  steadily  deeper.  If  the  roadway 
be  even  and  moderately  crowned,  wagons  pass  equally 
well  over  every  part  of  it,  and  no  permanent  tracks 
will  be  made.  Hence  the  surface  should  be  such 
that  travel  will  use  indifferently  the  whole  width. 
The  less  the  convexity  the  more  advantageous  for 
travel.  The  great  secret  of  the  maintenance  of  a  stone 
roadway  in  good  order  is  to  facilitate  travel  over  its 
ivliole  ividtJi. 

Provided  the  roadway  is  kept  in  proper  order,  a 
convexity  corresponding  to  I  inch  to  the  yard  is  suffi- 
cient for  good  drainage,  and  favors  free  circulation 
over  the  whole  width.  This  is  the  convexity  pre- 
scribed by  Macadam,  and  is  the  one  adopted  on  the 
best  English  and  French  roads.  This  is  of  course 
after  the  roadway  has  become  thoroughly  solidified 
and  reached  its  normal  condition  under  travel.  For 
a  newly-built  road,  however,  and  for  ordinary  stone 
roads  in  general,  a  slope  of  2  inches  to  the  yard  is 
found  best  in  practice. 


K&SUM&.  33 

Resume'. 

The  successive  steps  in  the  actual  building  of  a 
stone  road  are  ordinarily  as  follows : 

The  grade  is  first  determined,  whether  it  be  for  a 
road  on  an  entirely  new  line  or  for  an  old  one  which 
is  to  be  made  over.  Next  the  width  and  convexity 
to  be  given  to  it  are  decided  on.  Then  follows  the 
preparation  of  the  bed  to  receive  the  broken  stone. 
The  essential  conditions  are  that  the  surface  of  it 
shall  be  well  drained  and  that  it  shall  be  hard, 
dry,  and  smooth,  so  that  the  stones,  when^compacted 
under  the  roller,  shall  not  penetrate  it.  A  few  turns 
of  the  roller  over  it  are  often  advisable.  Some  engi- 
neers, especially  in  England,  spread  a  layer  of  gravel 
2  to  3  inches  thick  before  rolling,  unless  the  ground 
be  hard  and  dry.  As  to  whether  the  bed  shall  be 
made  horizontal  or  have  the  convexity  of  the  finished 
roadway,  practice  varies.  If  horizontal,  the  stone 
layer  is  made  thicker  in  the  middle,  where  the  wear 
is  inevitably  greatest,  in  order  to  give  the  required 
convexity.  Otherwise  the  stone  layer  is  of  uniform 
thickness  throughout,  and  the  convexity  of  the  earth 
bed  gives  drainage  to  any  water  that  may  find  its  way 
there.  But  if  the  stone  layer  is  as  impermeable  to 
water  as  it  should  be,  there  would  be  none  to  drain 
off.  In  view,  however,  of  possible  imperfection  in 
the  work,  the  bed  had  better  be  convex. 

Upon  this  bed  is  built  the  stone  roadway,  whether 


34  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

the  Telford  system  with  foundation,  or  the  Macadam 
system  without  foundation,  be  adopted.  The  latter, 
as  has  already  been  stated,  is  the  one  exclusively  used 
in  France  to-day. 

Under  the  Macadam  system  the  stone  layer  con- 
sists of  stone,  generally  of  one  kind  only,  broken  as 
nearly  as  practicable  to  a  uniform  size.  Sometimes 
this  is  all  spread  at  once  and  then  rolled.  If,  how- 
ever, the  road  is  to  be  of  standard  thickness,  it  will  be 
more  solid  and  durable  if  the  total  quantity  be  spread 
in  two  layers,  and  the  first  is  well  rolled  before  the 
top  one  is  spread.  This  is  especially  true  if  a  lighter 
horse-roller  is  used  instead  of  the  heavy  steam-roller. 
If  no  roller  at  all  is  to  be  had,  then  ordinary  travel 
must  do  the  work  of  compacting  the  stone,  which  was 
Macadam's  original  method.  Rollers  were  first  used 
in  England  about  1830.  He  spread  4  inches  at  first, 
assuming  that  10  inches  in  all  of  loose  stone  were  to 
be  used,  and  when  this  had  become  sufficiently  solid 
under  travel,  a  layer  of  3  inches  more,  which  is,  in 
turn,  subjected  to  travel,  and  finally  the  top  layer  of 
3  inches.  At  the  present  day,  however,  the  great 
convenience  and  advantage  of  thorough  rolling  is 
fully  appreciated.  It  not  only  brings  the  road  at 
once  into  perfect  condition,  but  it  consolidates  far 
better  the  mass  of  stone  and  makes  the  roadway  the 
compact,  impermeable  body  desired. 

The  heaviest  roller,  within  practicable  limits,  is 
the  best,  and  the  greater  the  compression  the  more 


35 

solid  is  the  roadway.  The  number  of  times  a  roller 
must  pass  over  a  given  point  in  order  to  secure 
complete  solidification  varies  much  with  different  cir- 
cumstances. 

1.  It  increases  in  proportion  to  the  hardness  of  the 
stone.     Assuming   that  the  layer  is  3  inches    thick, 
and  that  a  10-  or  1 2-ton  roller  is  used,  50  times  are 
sufficient   with    ordinary   limestone,    50    to    75    times 
with  granite,  and  90  to   100  times  with  porphyry  or 
trap. 

2.  It  increases  with  the  thickness  of  the  layer  to  be 
rolled,  but  not  in  proportion  to  the  thickness. 

3.  It  is  more  if  the  stones  are  dry  than  if  they  are 
wet.      Abundant  watering  at  the  moment   of  rolling 
facilitates    compression,  transforms    the    loose    stones 
into  a  monolith,  avoids  the  pulverization  of  the  stone, 
and  is  every  way  more  economical.      Great  care  must, 
however,   be    taken   to    use    the   water    in    such   way 
and   quantity   as   not  to   soften  the  ground   beneath. 
Where   this   is    not   exceptionally   hard    and    solid   it 
would  be  better  at  first  to  roll  dry. 

When  the  rolling  is  nearly  finished,  and  not  till 
then,  a  layer  1/3  of  an  inch  thick  of  clean  gravel  is 
spread  over  the  surface,  and  the  road  is  ready  for 
travel. 


OF  THE 

UNIVERSITY; 


36  ROADS  AND    PA  VEMENTS  IN  FRANCE. 


IV.   MAINTENANCE  AND  REPAIR. 

The  importance  of  keeping  a  stone  road  always  in 
good  condition  is  so  great  from  every  point  of  view 
that  it  would  seem  unnecessary  even  to  mention  it 
were  it  not  that  in  so  many  cases  roads  thoroughly 
well  made  have  been  allowed  to  deteriorate  simply 
for  want  of  moderate  care  and  attention.  It  seems 
hardly  worth  while  to  incur  the  necessary  expense  of 
building  a  good  road  if  it  is  to  be  so  neglected.  The 
old  adage,  "  A  stitch  in  time  saves  nine,"  is  emphati- 
cally true  of  stone  roads. 

In  the  maintenance  of  such  roads  there  are  two 
operations,  viz.,  the  use  of  the  material  to  replace 
that  used  up  and  the  removal  of  mud  and  dust  caused 
by  wear.  If  either  of  these  is  badly  done,  or  not 
done  at  the  proper  time,  the  roadway  deteriorates. 

There  are  also  two  quite  distinct  methods  of  repair. 

A.  That  which,  for  want  of  a  better  name,  may  be 
called  patchwork  repair.     This  is  the  older  method, 
and,  though  still  employed   upon  nearly  one  half   of 
the  Routes  Nationales,  is  being  replaced  gradually  by 
the  other  method. 

B.  That  by  general  recharging.      This,   the   more 
modern  one,  is  favored  where  it  can  be  applied,  but  it 
necessitates  the  use  of  a  horse  or  steam  roller. 


MAINTENANCE  AND    REPAIR.  37 


A.  PATCHWORK  REPAIR. 

This  method  consists  essentially  in  restoring  annu- 
ally to  the  roadway  a  quantity  of  broken  stone  equal 
to  that  lost  by  wear  during  the  year,  and  this  not  by 
spreading  a  layer  uniformly  over  the  surface,  but  by 
repairing  isolated  spots  or  patches,  where  from  wear 
or  other  cause  holes  or  depressions  show  themselves. 
The  intention  is  not  only  to  keep  the  surface  even 
and  insure  perfect  drainage,  but  also  to  preserve  con- 
stantly the  normal  convexity  and  thickness  of  the 
stone  layer. 

When  this  method  is  faithfully  carried  out  the 
result  is  an  excellent  road,  well  maintained,  but  at 
high  cost.  When,  however,  it  is  carelessly  or  ineffi- 
ciently applied,  as  is  not  unfrequently  the  case  on 
less  important  country  roads,  the  result  is  far  from 
satisfactory.  The  roadman  there  simply  spreads  the 
broken  stone,  assigned  to  his  section,  at  such  points 
as  he  thinks  require  it,  and  then  leaves  it  to  ordinary 
travel  to  do  the  rest.  This  can  never  give  a  good 
road. 

The  obvious  disadvantages  of  this  method  may  be 
diminished  if  the  following  precautions  are  carefully 
observed:  Notice  the  holes  and  depressions  immedi- 
ately after  a  heavy  rain ;  mark  them  by  lines  forming 
rectangles  around  them ;  pick  the  space  within  these 
rectangles  to  a  nearly  uniform  depth ;  separate  the 


38  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

stones  from  the  fine  material  and  pack  them  well 
inside  the  space  picked,  adding  more  if  required; 
make  them  solid  with  the  pounder,  without  the  addi- 
tion of  any  binding  material ;  repeat  the  pounding  if 
later  any  of  the  stones  be  displaced. 

Evidently  much  labor  must  be  expended  to  get 
good  results,  for  if  the  patches  cover,  say,  a  square 
yard  each,  a  roadman  will  hardly  be  able  to  use  more 
than  \\  cubic  yards  of  broken  stone  a  day,  and  con- 
sequently the  length  of  road  assigned  to  him  must  be 
disproportionately  small.  This  method  is  simple  but 
not  economical,  and  should  be  used  only  where  a 
0  general  recharging"  is  impracticable  or  unadvisable. 

As,  however,  its  adoption  may  be  unavoidable, 
some  further  details  may  be  noted.  The  roadmen 
have  a  tendency  to  frequently  renew  certain  muddy 
or  wet  places,  such  as  the  bottom  of  a  valley  or  in  a 
dense  wood,  and  especially  on  the  flanks  of  the  road- 
way. Such  points  are  often  muddy,  not  because  the 
stone  layer  is  too  thin,  for  it  not  unfrequently  is 
thicker  there  than  elsewhere,  but  because  the  drainage 
is  imperfect.  The  remedy  is  not  to  add  more  stone, 
but  to  scrape  away  the  mud.  The  flanks  of  the  road- 
way especially  should  be  so  treated,  for  they  are 
always  less  worn  by  travel  than  the  middle  of  the 
road,  and  any  mud  that  may  be  there  is  largely  ac- 
cumulation of  scrapings  from  the  middle.  The  flanks 
in  any  case  must  be  kept  clean,  and  this  is  generally 
enough.  If  the  roadway  is  not  more  than  16  feet 


MAINTENANCE  AND    REPAIR.  39 

wide  these  repair  patches  are  needed  only  on  the 
middle  10  feet. 

Since  this  method  contemplates  the  restoring  for 
the  whole  length  of  the  road  an  amount  of  stone 
equivalent  to  the  annual  wear,  it  is  evident  that  more 
must  be  added  than  just  sufficient  to  fill  holes  and 
depressions. 

The  way  sometimes  adopted  is  to  spread  at  once 
on  the  many  patches,  the  whole  length  of  the  sec- 
tion, the  year's  supply  of  stone  assigned  to  it,  and 
then  leave  it  to  travel  to  do  the  work  of  compacting. 
Nothing  could  be  much  more  objectionable.  The 
wagons  avoid  the  loose  stones  as  far  as  possible,  and 
the  roadway  suffers  in  consequence.  The  proper 
way,  assuming  that  no  roller  is  used  and  that  ordinary 
travel  must  do  the  work,  is  to  force  travel  to  pass 
over  the  whole  surface  by  obstructing  it  in  one  direc- 
tion and  facilitating  it  in  another.  To  effect  this  the 
first  patches  may  be  made  along  the  middle  of  the 
road  at  intervals  of  about  50  yards,  without  reference 
to  any  depressions  there  may  be  between.  These 
patches  have  the  shape  of  elongated  rectangles,  about 
3X8  feet. 

The  whole  section  having  been  gone  over  in  this 
way,  the  roadman  commences  again  at  the  original 
starting-point  and  makes  new  patches,  checker-board 
fashion,  alternately  on  the  right  and  left  of  the  first 
patches  and  midway  in  the  space  between  them,  care 


4O  ROADS  AND   PAVEMENTS  IN  FRANCE. 

being  taken  to  place  them  within  the  middle  three 
quarters  of  the  width  of  the  roadway. 

On  the  third  trip  he  makes  new  patches  between 
the  second  set,  and  so  on,  always  observing  the 
checker-board  arrangement. 

Thus  in  five  trips  the  whole  central  part  of  the 
roadway  has  been  covered,  while  travel  has  been  in- 
duced, without  serious  annoyance,  to  change  direc- 
tion five  times  and  virtually  to  pass  over  nearly  the 
whole  surface.  When  this  has  been  well  done  the 
roadway  is  perhaps  good  enough,  but  is  never  per- 
fectly solid  and  even. 

The  pounder  is  an  indispensable  tool  in  making 
good  repairs,  but  the  use  of  it  is  fatiguing,  and  is 
often  abandoned  or  neglected.  A  two-horse  roller 
is  often  used. 

The  cleanness  of  the  stone  added  has  already  been 
emphasized  in  the  section  on  road  construction.  It 
is  equally  important  in  repairs ;  hence  the  mixing  of 
sand  or  gravel  with  it  should  not  be  allowed,  for  the 
reasons  already  given.  The  objection  applies  with 
even  greater  force  to  the  use  of  clay  or  loam. 

Repair  of  Tracks  and  Ruts. 

Tracks  and  ruts  are  seldom  found  except  on  a 
roadway  that  has  been  badly  cleaned  or  badly  re- 
paired. The  first  step  is  to  scrape  off  the  accumu- 
lated mud,  dry  as  well  as  soft.  Sometimes  this  alone 


GENERAL   RECHARGING.  41 

will  restore  the  road  to  tolerable  condition,  and  unless 
the  wheel-tracks  have  worn  into  the  stone,  slight 
obstacles  may  be  placed,  sufficient  to  turn  the  travel, 
and  thus  gradually  restore  the  even  surface. 

Inexperienced  workmen  may  seek  to  remedy  the 
evil  by  filling  the  ruts  with  broken  stone ;  but  this 
rarely  answers  the  purpose,  for  a  new  track  will 
speedily  be  formed  by  the  side  of  the  old  one. 

If,  however,  the  track,  after  being  scraped,  appears 
too  deeply  worn  to  be  obliterated  by  the  means 
already  suggested,  nothing  remains  but  to  treat  it  as 
a  depression  and  thoroughly  pound  the  stone  in  it. 
This  is  obviously  a  costly  operation,  and  should  be 
resorted  to  only  to  save  the  road  from  complete  de- 
struction. 

The  stone  used  for  patch^vork  repairs  should  be  of 
the  same  kind  and  degree  of  hardness  as  that  of  the 
existing  road.  It  should  be  neither  harder  nor  softer, 
or  the  road  will  wear  unevenly.  If  softer,  it  is  more 
easily  worn  and  tends  to  make  holes.  If  harder,  it 
tends  to  produce  little  humps  and  to  deepen  the  low 
spots  about  them.  Thus  a  hard  trap  should  not  be 
used  for  patchwork  repairs  of  a  limestone  road. 

B.    GENERAL  RECHARGING. 

This  method  presupposes  the  use  of  a  horse  or 
steam  roller,  and  consists  in  allowing  the  roadway  to 
wear  away  gradually  until  it  has  reached  the  minimum 


42  ROADS  AND    PA  VEMENTS   IN  FRANCE. 

thickness  compatible  with  sufficient  resistance.  When 
this  condition  of  wear  has  been  reached,  the  whole 
surface  of  the  roadway  is  to  be  covered  with  broken 
stone,  sufficient  to  restore  it  to  its  normal  thickness 
and  convexity  ;  and  this  layer  should  be  as  thoroughly 
rolled  as  in  the  making  of  a  new  road. 

The  interval  between  two  successive  rechargings 
must  depend,  other  things  being  equal,  upon  the 
amount  of  travel.  It  may  be  three  or  four  or  possibly 
ten  years.  During  this  period  the  roadway,  if  entirely 
neglected,  would  be  covered  with  depressions  and 
holes,  more  or  less  serious.  An  even  and  conse- 
quently uniform  surface  may  be  secured  by  means  of 
the  ordinary  patchwork  repair,  restricted  solely  to 
this  purpose,  and  with  no  intention  whatever  of  re- 
storing the  annual  wear.  On  roads  where  travel  is 
moderate  such  repairs  are  scarcely  needed  at  all  for 
the  first  few  years  immediately  following  a  recharging. 

The  advantages  of  this  method  are  that  it  gives  to 
the  public  a  good  road  at  all  times,  and  is  economical 
of  material. 

The  disadvantages  are,  that  a  somewhat  harder 
stone  is  required,  and  that  the  normal  convexity  is 
not  maintained  during  the  whole  interval. 

Stone  roads,  in  fact,  do  not  wear  off  uniformly 
over  the  whole  width.  The  middle  portion  is  inevi- 
tably most  rapidly  worn,  and  if  the  recharging  is  too 
long  delayed  the  surface  becomes  hollowed,  and  is 
consequently  not  properly  drained. 


GENERAL   RECHARGPNG.  43 

In  France  the  tendency  is  to  substitute  this  method 
for  die  older  one,  and  in  1893  more  than  half  of  the 
stone  for  repairs  was  used  in  general  rechargings. 
This  method  is  used  exclusively  in  general  repairs  of 
the  macadamized  streets  of  Paris. 


Thick  ness  of  RecJiargings. 

The  thickness  of  stone  to  be  added  must  depend 
on  the  conditions  in  each  case.  Assuming  that  the 
roadway,  when  new,  had  a  thickness  of  8  inches,  and 
that  experience  had  shown  this  to  be  sufficient,  so  much 
stone  only  need  be  added  as  will  restore  the  layer  to 
its  original  thickness  and  convexity.  As  a  road  wears 
it  gradually  loses  its  convexity,  becomes  flat,  and 
finally  hollow  along  the  middle  if  repairs  are  delayed 
too  long.  The  sides  are  comparatively  little  worn  and 
evidently  require  little  or  no  fresh  material.  In  gen- 
eral, then,  the  recharging  may  be  confined  to  the  mid- 
dle portion  i^  to  2  feet  from  each  edge  of  the  roadway. 
In  the  majority  of  cases,  provided  the  wear  has  not 
been  allowed  to  go  on  up  to  the  last  possible  limit,  a 
recharging  which  when  compacted  has  a  thickness  of  4 
inches  is  amply  sufficient.  If  the  wear  is  well  within 
this  extreme  limit  an  average  thickness  of  2|-  to  3 
inches  of  new  stone  may  suffice,  say  1/3  of  a  cubic  yard 
per  running  yard  if  the  recharging  is  12  feet  wide,  or 
if  it  is  only  9  feet  wide,  24  cubic  yards  per  100  yards. 
It  is  sometimes  astonishing  to  see  how,  with  even  so 


44  ROADS  AND    PAVEMENTS  IN  FRANCE. 

slight   a  covering,  an   inferior   road   may   be   brought 
into  excellent  condition,  provided  it  is  well  rolled. 

A  recharging  only  8  feet  wide  along  the  middle  is 
much  better  than  nothing. 

Picking  of  the  Surface  for  Recharging. 

When  the  surface  of  the  roadway  does  not  need 
recharging  for  its  whole  width,  the  part  to  be  covered 
must  be  limited  and  defined  by  two  furrows  cut  length- 
wise of  the  road,  in  order  to  prevent  the  stone,  which 
may  be  added,  from  spreading  under  the  roller,  and 
also  to  insure  the  better  union  of  the  edges  of  the  new 
layer  with  the  undisturbed  margin  of  the  roadway. 
These  furrows  should  be  carefully  picked  out.  No 
other  picking  is  necessary.  The  practice  of  picking 
up  the  whole  surface  of  the  width  to  be  recharged 
is  common  enough,  but  the  utility  of  it  is  questionable. 
Why  destroy  at  considerable  expense  a  portion  of  the 
solid  layer,  which  is  already  as  thoroughly  compacted 
as  it  can  be?  Presumably  the  purpose  is  to  insure  a 
perfect  union  of  the  new  stone  with  the  old  body  of 
the  road,  but  this  can  be  effected  quite  as  well  in  an- 
other way  and  with  far  less  expenditure  of  labor. 

A  vigorous  scraping  and  sweeping  will  thoroughly 
uncover  the  old  surface.  There  is  always  a  greater 
or  less  thickness  of  mud  or  dust  on  a  roadway.  If 
this  is  not  removed  it  forms,  after  recharging,  a  thin 
layer  of  material,  as  objectionable  as  clay,  between  the 
old  bed  and  the  new — a  layer  analogous  to  that  which 


GENERAL   RECHARGING.  45 

separates  two  successive  beds  of  any  sedimentary 
formation.  This  layer  should  in  any  case  be  re- 
moved, and  can  be  by  thorough  scraping  and 
scratching  with  a  stiff  broom.  If  this  is  properly 
done  there  is  nothing  to  prevent  the  perfect  union  of 
the  new  stone  with  the  old  solid  road-bed.  It  is  worse 
than  useless  to  set  an  army  of  men  with  picks  to 
break  up  this  solid  bed  and  do  what  had  better  be 
left  undone.  A  good  stream  of  water  from  a  hose 
while  the  sweeping  is  going  on  aids  greatly  in  the 
perfect  removal  of  the  fine  material. 

Rolling. 

This  is  an  operation  as  essential  in  the  recharging 
as  in  the  building  of  a  road.  It  is  just  as  important  here 
as  there  to  compact  the  broken  stone  into  a  solid 
mass  and  get  rid  of  all  cavities.  By  rolling,  first,  the 
broken  stones  are  crowded  face  to  face,  and  lie  as 
closely  together  as  their  shapes  will  allow;  second, 
the  edges  and  angles  are  to  some  extent  crushed,  and 
the  fine  particles  fill  up  the  cavities.  Of  these  two 
results  the  first  is  evidently  the  better,  and  should  be 
facilitated  as  much  as  possible  by  diminishing  the 
friction  between  the  stones.  The  ideal  roadway  will 
be  realized  when  they  are  so  compacted  that  no  cavi- 
ties are  left  between  them.  This  ideal  may  be  ap- 
proximately reached,  when  the  stones  are  cubical  and 
of  uniform  size,  by  abundant  watering  before  and 
during  the  rolling. 


46  ROADS  AND    PAVEMENTS   IN  FRANCE. 

Watering. 

This  watering  is  indispensable  when  a  recharging 
is  made  at  a  dry  time  on  a  hard  foundation.  In  such 
case  the  stones  may  well  be  deluged  with  water;  the 
compacting  of  them  goes  on  more  rapidly  and  per- 
fectly, and  their  union  with  the  old  roadway  is  more 
complete.  The  excess  of  water  soon  drains  off,  and 
the  road,  after  a  few  days  of  fine  weather,  becomes 
exceptionally  hard  and  solid. 

At  a  dry  time  350  gallons  of  water  should  be  used 
daily  for  every  100  running  feet.  During  a  wet  time 
k-ss  watering  is  necessary,  and  the  operation  is  conse- 
quently more  economical. 

Binding  Material. 

No  binding  material  should  be  mixed  with  the 
stones  in  a  recharging  any  more  than  in  the  building 
of  a  road.  Here  as  well  as  there  a  perfect  bind, 
better  and  more  enduring,  may  be  secured  by  rolling 
than  by  the  use  of  gravel.  Gravel  may,  however,  be 
advantageously  used  after  the  rolling  has  consolidated 
the  stones,  spread  as  a  layer  not  exceeding  one  third 
of  an  inch  thick,  in  order  to  fill  the  small  interstices 
that  may  be  left  in  the  mosaic. 

Some  have  strongly  advocated  a  method,  which 
consists  in  spreading  on  the  old  roadway  a  thin  layer 
of  sand  or  sifted  gravel  before  the  recharging.  Upon 


w 


JNIVJERSIT 

GENERAL   RECHARGING.  47 

this  the  broken  stone  is  spread,  thoroughly  watered, 
and  rolled.  They  claim  that  the  sand  or  gravel  be- 
comes semi-fluid  and  is  squeezed  up  among  the  stones, 
and  that  it  acts  in  the  same  way  as  a  binding  material 
mixed  with  the  stones.  It  certainly  does  favor  the 
more  rapid  packing  of  the  stones  in  a  certain  way,  and 
is  a  less  expensive  operation  than  that  recommended 
above,  but  it  cannot  fail  to  impair  the  final  solidity  of 
the  road,  and  hence  is  not  real  economy.  A  recharg- 
ing made  with  as  much  water  as  practicable  and  the 
least  possible  quantity  of  binding  materiaj  will  always 
be  the  solidest. 

The  rolling  of  a  new  roadway,  as  has  already  been 
stated,  should  be  done  in  fine  weather,  when  the  sur- 
face of  the  foundation  soil  is  dry  and  hard. 

The  rolling  of  rechargings,  on  the  contrary,  may 
better  be  done  after  several  rainy  days  have  helped  to 
clean  off  the  old  roadway  and  to  soften  somewhat  the 
surface. 

The  edges  should  first  be  rolled,  and  the  centre  not 
before  both  edges  have  been  somewhat  compacted. 
The  first  turn  of  the  roller  on  the  border  should  over- 
lap about  8  inches  on  the  old  solid  part.  It  will  be 
remembered  that  the  furrow,  cut  with  a  pick,  was  in- 
tended to  narrow  the  part  to  be  recharged,  and  was  to 
be  cut  in  such  way  as  to  form  a  shoulder  against  the 
thrust  of  the  stone  under  the  roller. 

When  one  margin  has  been  rolled  the  same  operation 
is  repeated  on  the  other  margin,  and  so  on  pro- 


48  ROADS  AND    PAVEMENTS  IN  FRANCE. 

gressively  toward  the  centre,  care  being  taken  that  each 
turn  shall  overlap  about  8  inches  of  the  part  already 
rolled  ;  the  stone  should  be  thoroughly  watered  during 
the  rolling.  The  rolling  should  be  continued  till  the 
mass  is  solid  and  does  not  undulate  under  the  roller 
or  yield  on  the  passage  of  a  loaded  wagon.  Not  till 
then  should  the  thin  layer  of  binding  gravel  be  spread, 
not  to  penetrate  into  the  body  of  the  roadway,  but 
only  to  fill  the  interstices  of  the  surface. 

A  small  quantity  of  the  stone  should  be  reserved  to 
fill  any  depressions  developed  during  the  rolling  and 
to  keep  the  surface  even. 

If  the  surface  of  the  old  road  be  in  very  bad  condi- 
tion, with  many  holes  and  ruts,  these  last  may  be 
filled  and  pounded  or  rolled  in  order  to  prepare  a 
tolerably  even  surface  for  the  recharging  proper.  In 
the  worst  cases  the  recharging  may  be  made  in  two 
operations,  the  lower  layer  being  of  inferior  and  less 
expensive  stone.  But  in  all  cases  the  top  layer  should 
be  of  the  harder  stone  (if  there  is  any  difference),  never 
of  the  more  tender,  and  under  no  circumstances  an 
indiscriminate  mixture  of  hard  and  soft  stone. 

To  insure  perfect  work  the  road  should  be  watched 
for  some  little  time  after  a  recharging  and  watered  regu- 
larly. Stones  that  may  have  become  loose  should  be 
removed ;  any  parts  injured  by  some  accidental  cause 
be  pounded ;  and  by  occasional  sweeping  all  wheel- 
tracks  obliterated,  in  order  that  travel  may  be  induced 
to  circulate  over  the  whole  width. 


GENERAL   RECHARGING.  49 

The  following  is  given  by  Monsieur  Debaure  as  an 
average  cost,  per  cubic  yard  of  material,  of  a  recharg- 
ing covering  a  width  of  about  10  feet,  with  an 
average  thickness  of  2\  to  3  inches.  This  allows 
8  to  9J  cubic  yards  per  100  running  feet.  It 
is  exclusive  of  the  cost  of  the  broken  stone  and 
gravel.  It  assumes  the  use  of  a  hard  stone,  like  trap 
for  instance,  rolled  dry  with  a  zo-ton  steam-roller. 
The  cost  would  be  about  20  per  cent  less  if  rolled 
wet  and  if  a  softer  stone  were  used.  The  average 
wages  of  an  ordinary  roadman  are  from  65  to  70  cents 
a  day. 

Cost  per 
cubic  yard. 

Cents. 
Picking  the  furrows  and  preparation i 

Spreading  the  broken  stone. 7 

Finishing  off  and  spreading  gravel 4 

Cost  of  water  and  watering , 13 

Rolling,  oiling,  and  small  repairs  of  roller.  13 

Wear  of  roller  and  large  repairs 5 

43 

A  lO-ton  steam-roller  can  effectively  roll  in  a  day 
328  running  feet  (100  metres)  of  such  a  recharging 
as  above  indicated.  The  cost,  if  a  horse-roller  were 
used,  would  be  about  30  per  cent  greater. 

In  the  Department  of  Oise,  under  M.  Debaure's 
charge,  130,000  cubic  yards  of  broken  stone  are  used 
annually  for  general  rechargings. 


50  ROADS  AND   PAVEMENTS  IN  FRANCE. 

Modified  Recharging. 

After  a  very  severe  winter  or  following  an  excep- 
tionally heavy  travel  a  roadway  may  have  become  very 
uneven,  full  of  holes  and  ruts,  and  quite  out  of  order, 
while  the  stone  itself  is  not  much  worn.  The  time 
for  a  regular  recharging  has  not  yet  come,  and  yet 
heavy  repairs  are  demanded  immediately.  Recourse 
in  such  case  may  advantageously  be  had  to  a  modi- 
fied recharging,  with  use  of  the  roller.  From  4  to 
8  cubic  yards  of  stone  per  300  feet  of  length,  corre- 
sponding to  about  1/6  to  1/3  of  a  regular  recharging, 
may  be  spread  at  once  where  needed  along  the  middle 
of  the  road  and  in  the  low  spots,  the  edges  of  these 
spots  having  first  been  picked.  Wet  weather  is  availed 
of  for  this  operation,  and  the  roller  is  passed  about  a 
dozen  times  at  most  over  the  stone. 

This  operation,  if  well  done  and  at  a  favorable  season, 
gives  excellent  results,  and  restores  to  good  condition 
a  roadway  that  in  appearance  is  nearly  ruined.  This, 
however,  should  be  regarded  only  as  a  remedy  in  an 
emergency,  and  is  not  to  be  substituted  for  the  sys- 
tem of  general  recharging.  But  it  is  infinitely  better 
than  the  method  of  patchwork  repair,  as  generally 
applied.  These  patclies,  when  made  all  at  one  time, 
in  a  large  number  of  spots,  cause  great  annoyance  to 
travel,  and  almost  never  effect  an  improvement  com- 
mensurate with  the  expenditure. 


TYPICAL   FRENCH  ROADS.  $1 

Scraping  and  Sweeping. 

The  removal  of  mud  and  dust  as  soon  as  it  is 
formed  is  necessary  to  keep  the  roadway  in  perfect 
order,  and  the  roadway  suffers  just  in  proportion  as 
this  is  neglected.  In  no  other  way  can  the  formation 
of  tracks  be  so  well  prevented,  and  the  complete 
drainage  of  the  surface  insured. 

Typical  French  Roads. 

The  following  sections  of  typical  French  roads, 
taken  from  Debaure's  treatise,  shows  the  methods  of 
construction  adapted  to  different  conditions  of  topog- 
raphy and  travel : 


Fig.  4  is  a  section  of  the  type  of  road  in  the 
Department  of  Seine-et-Oise,  and  is  regarded  as  a 
good  one  where  there  is  considerable  travel.  The 
macadamized  portion  is  16^  feet  wide,  with  paved 
edges  each  about  3  feet  wide ;  the  sidewalks  are 
about  6  feet  wide,  with  a  slope  of  I  in  20.  The 
convexity  of  the  macadam  is  1/40,  or  nearly  2  inches 
to  the  yard  from  centre  to  edge. 


XOADS  AND    PA  VEMENTS  IN  FRANCE. 


Fig.  5  is  the  type  of  roads  in  the  Department  of 
Bas-Rhin.  The  width  of  macadam  is  19 j  feet,  with 
a  gravel  or  grass  margin  on  each  side6  ^  feet  wide. 
The  ditches  are  5  feet  wide  at  the  top  and  20  inches 
deep.  The  macadam  is  unnecessarily  wide,  16^  feet 


— Lao".! -20 -20*:. 6-7-"---  --1 — 9-10- 


FIG.  5. 

being  amply  sufficient.     The  convexity  is  1/50,  or  i|- 
inches  to  the  yard. 


FIG.  6. 

Fig.  6  represents  a  type  in  the  Department  of 
Loiret.  The  macadam  is  16^  feet  wide,  with  gravel 
edges  each  20  inches  wide,  and  raised  margins  of 
turf  6  feet  wide.  The  drainage  into  the  side  ditches 
is  effected  by  means  of  small  cuts  at  short  intervals 


TYPICAL   FRENCH   ROAJJb. 


53 


through  this  turf  margin.    The  convexity  is  1/50,  or  I  ^ 
inches  to  the  yard. 

Fig.  7  is  a  section  of  one  of  the  ' '  Routes  Nationales ' ' 
in  the  Department  of  Haute- Vienne,  where  the  road 
is  built  upon  an  embankment.  The  macadam  is  19^- 
teet  wide ;  upon  one  side  a  footway  3  feet  wide  is 


-1--3V-11- O'l0- -"- -9-10- lj-_ 


raised  18  inches  above  the  edge  of  the  macadam. 
The  drainage  is  by  pipes  or  uncemented  but  covered 
stone  drains  passing  under  this  sidewalk.  The  con- 
vexity of  the  roadway  is  1/40,  or  nearly  2  inches  to  the 


---5-8-'---'-20L2(P  -----  5-'  ---------  8-3-"-  -----  '•-  ------  &'s-  ----  -1  ----  -5-—  Igo'Uo-  ----  -7-3-"  ----- 


Fig.  8  represents  a  departmental  road  in  the 
Department  of  Eure.  The  width  of  the  stone  portion 
is  i6J-  feet,  with  gravel  or  turf  margins  each  5  feet 
wide.  The  total  width,  including  ditches,  is  33  feet. 


(UNIVERSITY 

\  ne 


54 


ROADS  AND    PA  VEMENTS  IN  FRANCE. 


The  stone  roadway  is  formed  of  two  layers,  each  6 
inches  thick ;  the  bottom  layer  is  of  large  stones,  and 
the  top  layer  of  broken  stone  2\  inches  in  diameter. 
The  convexity  is  about  1/36,  or  2  inches  to  the  yard. 


FIG.  9. 

Fig.  9  represents  a  road  of  the  first  class  in  the 
Canton  Vaud,  in  Switzerland.  The  width  of  the 
macadam  is  1 5f  feet,  which  will  allow  two  carriages  to 
pass,  with  margins  each  3  feet  wide  of  gravel.  The 
convexity  is  1/40,  or  nearly  2  inches  to  the  yard.  The 
slopes  of  cuts  and  embankments  are  generally  I  of 
height  to  i^  of  base.  Slopes  steeper  than  that  would 
be  gullied,  and  difficult  to  maintain. 


Fig.    10   is  the  section   of   a    country  road  in  the 
Department  of  Indre-et-Loire.     The  macadam  is   10 


TYPICAL  FRENCH  ROADS.  55 

feet  wide,  flanked  with  a  margin  on  each  side  of  5 
feet  of  gravel  or  turf.  For  roads  of  this  kind  10  feet 
of  macadam  is  quite  sufficient.  A  width  of  13  feet, 
which  width  is  often  adopted,  has  the  disadvantage  of 
being  unnecessarily  great  for  one  carriage,  and  yet  not 
enough  for  two.  The  convexity  is  1/20,  or  3^  inches 
to  the  yard,  which  is  excessive. 


$6          ROADS  AND   PAVEMENTS  IN  FRANCE. 


TREE  PLANTATIONS. 

IN  a  country  so  thickly  populated  as  France  the 
economical  use  of  all  available  land  is  a  matter  of  im- 
portance, arid  the  desire  to  utilize  the  margins  of  high- 
ways, which  would  otherwise  be  waste  land,  by  the 
growth  of  trees  has  been  one  reason  why  the  planting 
of  trees  upon  the  borders  of  most  of  the  public  country 
roads  has  received  so  much  attention  and  care.  But 
the  reasons,  equally  strong  there  and  of  greater  weight 
in  our  country,  are  the  agreeable  shade  which  trees 
give  to  the  traveller  during  summer,  and  the  influence 
they  have  in  preserving  the  roadway  during  periods  of 
dryness.  In  hilly  and  mountainous  districts,  where 
the  deep  winter  snows  cover  everything,  the  trees  are 
especially  useful  in  marking  the  line  of  roadway. 

It  is  therefore  not  surprising  that  tree-planting  on 
the  highways  has  for  a  century  been  the  subject  of 
royal  decrees  and  legislative  enactments,  determining 
the  kinds  of  trees  to  be  planted,  manner  of  planting, 
care  of  them,  penalties  for  injury  to  them,  etc.  For 
instance,  in  1851  it  was  ordered  that  the  trees  planted 
should  be  of  species  appropriate  to  the  soil  and  climate, 
and  as  far  as  practicable  those  that  would  have  a 
marketable  value,  such  as  elm,  ash,  oak,  and  chestnut 


TREE  PLANTATIONS.  57 

among  the  harder  woods  of  slow  growth,  and  among 
the  softer  woods  poplar,  plane,  sycamore,  and  acacia. 
Certain  kinds,  such  as  fruit-trees,  walnut,  wild  cherry, 
and  apple,  were  to  be  always  excluded. 

In  1880  the  report  of  the  engineers  was  adverse 
upon  certain  plantations  of  cherry,  walnut,  pear,  apple, 
almond,  chestnut,  and  mulberry  trees,  upon  the  ground 
that  the  fruits  were  stolen  and  the  trees  injured. 
Forest  trees  were  preferred. 

The  utility  of  shade-trees  in  preserving  the  surface 
of  the  roadway  during  the  dry  heat  of  summer  is  the 
more  evident  where  the  material  of  which  the  road  is 
built  is  quickly  drained.  One  result  of  the  constant 
care  bestowed  upon  the  main  highways  at  the  present 
day  is  that  they  are  solid  and  perfectly  drained,  and  in 
the  majority  of  cases  suffer  more  injury  from  dryness 
than  from  moisture.  Hence  shade-trees  are  of  special 
value  on  long  stretches  of  level  road  in  an  open 
country  swept  by  drying  winds.  On  the  other  hand 
shade-trees  should  not  be  planted  in  low,  wet  places, 
or  where  the  roadway  is  not  readily  dried. 

The  method  of  planting  is  influenced  by  the  width 
of  the  road.  Many  of  the  old.  Routes  Nationalcs 
were  laid  out  originally  over  65  feet  wide,  where  to-day 
a  roadway  of  16  feet  width  is  amply  sufficient  for 
present  travel.  The  turf  margins  are  in  such  cases 
frequently  planted  with  a  double  row  of  trees  upon  each 
side  of  the  roadway.  As  a  general  rule,  when  the 
roads  are  50  feet  or  more  in  width,  two  rows,  10  feet 


58  ROADS  AND    PAVEMENTS   IN  FRANCE. 

apart,  are  planted  on  each  margin,  the  trees  in  each 
row  being  33  feet  apart,  placed  alternately. 

On  roads,  which  are  from  33  to  50  feet  in  width,  one 
row  only  is  planted  on  each  margin  with  trees  33  feet 
apart. 


COST  OF  CONSTRUCTION.  59 


COST   OF  CONSTRUCTION. 

Statements  of  the  cost  of  building  roads,  unac- 
companied by  full  details  of  the  conditions  in  each 
case,  have  only  a  general  interest.  Not  only  are  the 
elements  which  make  up  the  cost  different  in  differ- 
ent countries,  but  they  are  by  no  means  the  same 
in  all  parts  of  the  same  country,  or  even  of  the  same 
district. 

The  amount  and  kind  of  travel  to  be  provided  for, 
the  importance  of  the  road  and  its  width,  the  grading 
required,  the  special  engineering  obstacles  to  be  over- 
come, the  cost  of  broken  stone,  the  local  wages  of 
labor  and  other  similar  considerations  necessarily 
modify  very  materially  the  cost  in  each  case.  It  is 
one  thing  in  New  England,  where  gravel  is  abundant 
and  good  rock  near  at  hand,  and  quite  another  on  the 
broad  prairies  of  the  West. 

This,  then,  being  understood,  the  following  state- 
ments of  cost  are  given  for  what  they  may  be  worth 
as  general  indications : 


60          ROADS  AND   PA  VEMENTS  IN  FRANCE, 

UNITED  STATES. 

Mr.  James  Owen*  states,  as  the  result  of  many 
years'  personal  experience  in  building  roads  on  the 
Telford  system  in  New  Jersey,  that  "roads  built  in 
the  manner  I  have  described  [6  to  8  inches  thick  in- 
cluding the  stone  foundation]  cost  in  Essex  County, 
N.  J.,  60  to  80  cents  a  lineal  foot,  16  feet  wide, 
according  to  their  thickness  and  distance  the  material 
has  to  be  hauled,  including  foundations  of  quarry- 
stones.  This  would  be  $3000  to  $4000  a  mile.  By 
using  local  stone  for  foundation  and  local  help  in  haul- 
ing, and  as  much  as  possible  local  labor,  and  also  re- 
ducing on  many  of  the  local  roads  to  14  feet  and  even 
12  feet,  I  think  the  cost  throughout  the  State  [Massa- 
chusetts] might  be  placed  at  $2500  per  mile,  provided 
due  economy  and  wise  administration  are  secured." 

FRANCE. 

The  following  figures  are  compiled  from  the  returns 
published  by  the  Minister  of  the  Interior: 

CJtem ins  Vicinaux.  f 

During  the  period  of  six  years,  from  1881  to  1886, 
inclusive,  there  were  built,  under  the  operation  of  the 

*  Address  on  Highway  Construction  in  New  Jersey.  By  James 
Owen,  C.E.  Pub.  of  the  Mass.  Soc.  for  Promoting  Agriculture, 
1893. 

f  See  Appendix,  "Classification  of  Roads  in  France." 


COST  OF  CONSTRUCTION, 


61 


law  of  March  12,  1880,  25,994  miles  of  stone  road  at 
a  total  cost  of  $57,404,789.  They  are  subdivided 
into  three  classes: 


Class  of  Road. 

No.  of 
Miles. 

Average 
Cost  per 
Mile. 

Total  Cost. 

Chemins 
Chemins 

de  grande  communication.  . 
d'interet  commun          .      .  . 

3,486 

5  08  1 

$2,926.50 
2  ^OQ   I  6 

$10,201,820 
II  7^2  8^2 

Chemins 

vicinaux  ordinaires  

17  dl6 

2  0^6.64. 

qe  470  177 

25,933 

$2,209.32 

$57,404,789 

These  general  figures  cover  the  whole  cost  of  the 
roads,  excepting  for  bridges,  culverts,  and  such  struc- 
tures. They  include  not  only  the  cost  of  the  road- 
way proper,  but  also  the  expenditure,  whatever  it  may 
have  been  in  each  case,  for  grading  and  the  right  of 
way,  where  necessary.  Unfortunately  the  reports  do 
not  show  separately  these  special  expenditures,  or  the 
cost  of  different  parts  of  the  work,  labor,  material,  etc., 
and  hence  do  not  admit  of  as  complete  an  analysis  as 
would  be  desirable.  Such  as  is  possible  is  given 
below. 

The  returns  are  from  86  of  the  87  Departments 
into  which  France  is  divided,  and  give  the  number  of 
miles  of  each  class  of  road  built  and  the  total  cost  in 
each  one  of  the  Departments.  The  range  of  cost  is 
very  great.  Thus  in  6  Departments  all  of  the  roads, 
aggregating  400  miles,  were  built  at  a  cost  of  not  ex- 
ceeding $800  a  mile.  In  13  Departments  310  miles 


62  ROADS  AND   PAVEMENTS  IN  FRANCE. 

cost  approximately  $5600  a  mile,  and  in  3  Departments 
380  miles  cost  about  $7200  a  mile. 

Obviously  the  conditions  of  every  sort  must  have 
been  exceptionally  faverable  in  the  first  case,  and  very 
exceptionally  unfavorable  in  the  last  two  cases. 
Between  these  extremes  are  all  grades  of  cost,  but  the 
returns  show  that — 

Chemins  de  grande  Communication. 
Number  of  miles  built  in  86  Departments  is  3486|. 

No.  of  Percentage  of        Approximate 

Depts.  3486f  Miles.          Cost  per  Mile. 

17 43  $1600 

7 7  2400 

1 8 20  3200 

8 7  4000 

4 6  4800 

7 5  S^oo 

Chemins  a"  Interet  Commun. 

Number  of  miles  in  86  Percentage  of 

Departments  is  5081.  5081  miles. 

22 45  l6o° 

13 j 22  2400 

17 21  3200 

2 I  4000 

4 2          4800 

6..  2         5600 


DIVERSITY/ 
COST  OF  CONSTRUCTION^Q^  63 


CJiemins  Vicinaux  Ordinaires. 

Number  of  miles  in  86  Percentage  of 

Departments  is  17,416.  17.416  miles. 

7 ...    ii  1300 

17 37  1600 

15 1 8  2000 

16 17  2250 

ii ii  2550 

5 3  2900 

5 3  3200 

From  which  it  appears  that  nearly  one  half  of  the 
whole  number  of  miles  of  each  class  cost  approxi- 
mately $1600  a  mile,  that  being  the  average  cost  per 
mile  in  each  one  of  56  Departments. 


64  ROADS  AND  Psi  VEMENTS  IN  FRANCE. 


COST  OF  MAINTENANCE. 

Routes  Nationales. 

These  are  maintained  by  the  national  government. 
The  annual  appropriation  covers  expenditure  of  every 
kind  for  ordinary  and  extraordinary  repairs  and  im- 
provements, and  is  apportioned  among  the  87  depart- 
ments, generally  in  proportion  to  the  number  of  miles 
taken  in  connection  with  the  amount  of  travel. 

Great  care  is  taken  to  ascertain  what  this  travel  is, 
in  order  to  insure  an  equitable  distribution  of  the 
appropriation.  *  Once  in  six  or  seven  years  a  com- 
mission of  competent  officials  of  the  Bureau  of  Bridges 
and  Roads  thoroughly  investigates  the  question.  Their 
labors  extend  through  twelve  months,  and  their  report 
is  full  of  elaborate  and  carefully  analyzed  details.  The 
choice  of  the  several  posts  of  observation  is  evidently 
one  of  the  most  difficult  and  important  parts  of  the 
work.  The  23,500  miles  (including  1500  miles  of 
block-stone  pavement)  are  divided,  according  to  cir- 
cumstances, into  sections  of  two  to  ten  miles  each,  but 
averaging  four  and  one  half  miles.  The  posts  of  ob- 

*  Ministere  des  Travaux  Publics.   Routes  Nationales.     Recense- 
roent  de  la  Circulation  en  1888. 


COST  OF  MAINTENANCE.  65 

servation  were  (in  1888)  4734.  The  point  was  to  de- 
termine the  amount  of  travel  that  passes  over  each 
section  during  each  twenty-four  hours  of  the  year.  It 
was  assumed  that  an  exact  record  of  what  passed  each 
post  during  28  days,  selected  out  of  the  twelve  months, 
would  give  a  fair  average.  Accordingly  the  record  was 
made  every  thirteen  days  from  January  3d  to  Decem- 
ber i Qth,  thus  giving  seven  days  and  each  day  of  the 
week  in  each  quarter  of  the  year. 

The  "unit"  adopted  to  express  the  amount  of 
travel  was  each  horse  harnessed  to  a  loaded  wagon, 
and  in  order  to  reduce  all  the  observations  to  this 
standard  unit  the  following  values  were  given,  viz.  : 

1.  Each  horse  hauling  a  public  vehicle  or  a  cart 

loaded  with  produce  or  merchandise I 

2.  Each  horse  hauling  an  empty  cart  or  a  private 

carriage 1/2 

3.  Each  horse,  cow,  or  ox  unharnessed,  and  each 

saddle-horse 1/5 

4.  Each  small  animal  (sheep  or  goat) J/S0 

The  results  of  these  extended  observations  were 
accepted  as  giving  a  very  close  approximation  to  the 
actual  amount  of  travel,  as  affecting  the  wear  of  the 
roadway. 

The  official  report  gives  the  average  travel  in  each 
Department.  Excluding  a  few  Departments  where  the 
travel  was  quite  exceptionally  large  or  small,  it 
ranged  generally  between  100  and  400  "  units  "  in  the 


66  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

twenty-four  hours.  The  general  average  of  all  Depart- 
ments was  170.6  "units." 

It  is  generally  assumed  that,  where  the  conditions 
are  the  same,  the  wear  of  the  roadway  is  in  direct 
ratio  with  the  amount  of  travel,  but  the  conditions 
may  vary  considerably.  A  mountain  road  subjected 
to  the  wash  from  heavy  rains  and  melting  snows  may 
easily  lose  more  material  from  its  surface  and  dete- 
riorate more  rapidly  with  little  travel  than  a  much- 
frequented  road  in  a  level  country. 

The  quality  of  the  broken  stone  used  in  different 
districts  influences  very  materially  the  quantity  re- 
quired for  repairs.  As  has  already  been  stated,  in  a 
scale  of  quality  from  o  to  20,  the  general  average  of 
all  Departments  is  10.85.  ^n  two  °f  the  Departments 
the  average  quality  is  only  6.40  and  6.90,  and  in  four 
it  is,  respectively,  16.23,  16.33,  16.65,  and  16.95. 
Considerable  quantities  of  qualities  3  and  4  are  used. 
It  is  evidently  thought  good  economy  to  use  to  so 
large  an  extent  the  inferior  but  cheaper  material  near 
at  hand,  rather  than  the  better  but  more  costly  one 
brought  from  a  distance. 

TOTAL  AVERAGE  COST,  LABOR  AND  MATERIALS. 

From  the  Official  Reports  it  appears  that  there  are 
in  France  321,803  miles  of  stone  roads  of  the  various 
classes,  upon  which  the  annual  expenditure  for  main- 
tenance, including  improvements  and  repairs,  is  ap- 
proximately $31,551, 860. 


COST  OF  MAINTENANCE.  67 

iu;i»»  Annual         Annual  Cost 

les-         Total  Cost.         per  Mile. 

Routes  Nationales 72.009  $4»333»5°°  $225  During  year  1893 

Routes  Departmentales..     16,188  2,794,723  172  1      Annual  average 

Grands  Vicinaux  128,522  15,835.100  123  i-      for  three  years, 

Petits  Vicinaux 155,093  8,488,537  55  j       1886,1887,1888. 

321,803  31,551,860 

These  figures  represent  the  outlay  for  materials  and 
for  labor  on  the  roadway  proper.  About  45  per  cent 
must  be  added  thereto  to  cover  expenditure  for  water- 
courses, sidewalks,  planting  of  trees,  and  for  general 
administration. 

ROUTES  NATIONALES. 
General  Averages  for  Year  1893, 

Number  of  miles 22,009 

Average  travel  in  24  hours,  "  units" 170.6 

Broken  stone,  including  7^  per  cent  of  binding 
gravel,  per  mile  and  100  "  units,"  cubic 

yards 49. 

Quality  of  stone,  scale  o  to  20,  average 10.85 

Average  cost  of  stone,  per  cubic  yard $1.17 

"  "    of  binding  gravel,  per  cubic  yard.       0.36 

Labor  cost  per  mile  and  100  "  units  " 30.71 

"         "      "    cubic  yard  of  material  used —       0.63 

Average  wages  of  roadmen  per  day 0.55 

Total  average  cost  per  mile  and  100  "  units:" 

Materials $58.75 

Labor 3O.7i-$89.46 

The  Average  Cost  of  Stone. 
The  average  cost  in   the  several  Departments  that 


68  ROADS  AND   PA  VEMENTS  IN  FRANCE. 

make  up  this  general  average  varies  very  considerably, 
and  seems  to  depend  as  much  on  the  proximity  of  the 
quarries  and  cheapness  of  quarrying  as  on  quality  of 
stone.  The  average  in  12  Departments  was,  severally: 

$0.53  per  cubic  yard  of  quality. . .  .No.  8.04 

..  "  7.19 

..  "  10.47 

..  "  9.70 

...  "  9.25 

...  "  6.40 

...  »  15.45 

...  "  13.80 

...  "  16.33 

...  "  16.95 

...  "  10.91 

..  "  14.25 

Average  Cubic  Yards  per  Mile  and  100  "Units" 

The  average  consumption  in  some  departments  is  as 
low  as  26  to  30  cubic  yards,  and  in  others  as  high  as 
60  to  65  cubic  yards.  This  wide  divergence  in  quan- 
tity used  is  due  in  part  to  differences  in  the  quality  of 
the  stone  used,  the  inferior  stone  wearing  out  faster; 
but  aside  from  that  there  are  differences  the  reasons 
for  which  are  not  stated  in  the  reports. 

The  writer  was  unable  to  obtain  corresponding  de- 
tails and  analysis  of  expenditures  for  the  maintenance 
and  repair  of  the  Routes  Departmentales,  Grands  Che- 
mins  Vicinaux,  and  Petit s  Chemins  Vicinaux. 


0.56 

O.OO     ' 

0.61    " 

«  <      <  <          (  < 

0.67    " 

tt      <  <          <  < 

0.73    "       " 

<  <      <  <          <  < 

1.96    " 

n      <  i          n 

2.20     " 

<  <      <  <          <  < 

2.27     " 

<  <      <  <          <  < 

2.38     " 

<  <      <  <          <  < 

2.40     " 

<  i      <  <          «  < 

2.78     "          " 

tt      (  <          (  « 

PA  VEMENTS   OF  PARIS.  69 


PAVEMENTS  OF   PARIS.* 

The  excellence  in  general  of  the  street  pavements 
of  Paris  and  the  intelligent  care  bestowed  upon  them 
by  the  government  and  the  highly  educated  body  of 
engineers  more  immediately  in  charge  justify  a  careful 
study  and  a  somewhat  detailed  account  of  the  mode 
of  construction  and  maintenance  of  the  several  kinds, 
the  conditions  to  which  each  is  suited,  as  well  as  the 
reasons  for  the  adoption  of  one  or  another,  and  in 
general  the  conclusions  reached  after  many  years  of 
experience  and  experiment. 

The  simple  facts  that  the  area  of  the  street  pave- 
ments exceeds  10,500,000  square  yards,  in  addition 
to  8,288,000  square  yards  of  sidewalks,  alleyways, 
etc.,  all  under  the  same  direction,  and  that  the  expen- 
diture for  the  year  1893,  exclusive  of  the  salaries  of 
officials  and  the  cost  of  new  constructions,  amounted 
to  $4,910,000,  are  sufficient  to  indicate  the  great  im- 
portance of  the  subject. 

Organization. 

The  "Service  of  the  Public  Ways"  is  primarily 
under  the  Prefet  of  the  Seine,  who  represents  the 

*  The  greater  part  of  what  relates  to  the  Pavements  of  Paris  is 
derived  from  "  Notes  a  1'appui  du  Compte  des  Depenses  de  1'Ex- 
ercice  1893,"  by  Monsieur  L.  Boreux,  1'Ingenieur  en  chef  de  la 
Voie  publique,  and  from  other  official  documents  furnished  by 
him  to  the  writer. 


?O  ROADS  AND    PAVEMENTS  JN  FRANCE. 

national  government,  but  is  specially  under  the 
direction  of  the  Board  of  Public  Works  of  Paris,  and 
immediately  in  charge  of  an  engineer-in-chief  of  the 
Fonts  et  Chaussees.  Under  him  are  eight  engineers 
of  the  Fonts  et  Chaussees,  each  of  whom  has  the 
responsible  charge  of  one  of  the  eight  sections  into 
which  the  twenty  wards  (arrondtssements)  of  Paris 
are  divided.  The  engineer-in-chief  has  under  his 
immediate  command  15  superintendents,  22  overseers, 
17  assistants,  and  2  office-boys.  Under  the  eight  sec- 
tion engineers  there  are  in  addition  108  superintend- 
ents, 1 1 1  overseers,  and  99  assistants. 

Each  section  is  subdivided  into  six  districts,  each 
under  the  immediate  charge  of  a  superintendent  and 
one  or  more  overseers  or  assistants,  according  to  the 
importance  of  the  service. 

In  all  of  the  sections  excepting  one  the  street-clean- 
ing is  under  the  direction  of  the  district  superin- 
tendents. 

The  figures  are  unfortunately  not  at  hand  to  show 
accurately  the  total  number  of  workmen  of  all  classes 
employed  in  the  street  service,  but  in  1893  the  num- 
ber was  considerably  more  than  5000,  of  whom  3500 
were  engaged  in  street-cleaning. 

The  engineer-in-chief  has  executive  control,  since 
August  i,  1892,  of— 

i.  All  new  constructions,  and  the  maintenance  of 
existing  highways  (streets,  sidewalks,  alleyways,  etc.) ; 
and 


PAVEMENTS   OF  PARIS,  71 

2.   The  cleaning  and  watering  of  these  public  ways. 

Under  the  first  head  are  embraced — 

(a)  Block-stone  pavements  and  the  working  of  the 
quarries  belonging  to  the  city ; 

(fr)  Macadam  pavements  and  the  steam-rollers,  in- 
cluding the  shops  for  the  repair  of  the  rollers ; 

(c)  Asphalt  pavements; 

(</)  Wooden  pavements,  including  the  purchase  and 
preparation  of  the  wood ; 

(e)  Bridges,  foot-bridges,  and  the  various  construc- 
tions connected  with  the  care  of  the  public  ways ; 

(/)  Control  of  the  cements,  the  laboratory  for  test- 
ing materials,  and  the  collecting  of  statistics  relating  to 
the  public  ways; 

(g)  Sidewalks,  alleyways,  improved  surfaces,  etc., 
and  the  supervision  of  the  establishments  for  the  prep- 
aration of  powdered  asphalt  and  of  bituminous  mastic ; 

(//)  The  laying  out  of  roads  for  private  owners. 

The  cleaning  of  the  streets  includes  the  watering, 
sweeping  and  removal  of  mud,  removal  of  snow  and 
ice  in  winter,  removal  of  house  refuse,  and  the  man- 
agement of  the  shops  for  the  repair  of  material. 
These  shops  serve  also  for  the  repair  of  the  steam- 
rollers and  tools  used  in  paving,  but  60  per  cent  of 
the  expense  is  chargeable  to  street-cleaning. 

Different  Classes  of  Streets. 

From  the  point  of  view  of  maintenance  and  control 
the  streets  are  divided  into  "Classified"  and  "  Un- 


72  ROADS   AND   PA  VEMENTS  IN  FRANCE. 

classified."  The  former  are  public  highways  in  every 
sense,  and  are  public  property.  The  adjacent  proprie- 
tors are  charged  in  the  first  instance  with  the  whoie 
cost  of  the  first  pavement.  After  the  street  has  been 
accepted  as  a  public  way  it  is  maintained  at  the  public 
cost. 

The  "unclassified"  streets  are  private  ways,  and 
are  wholly  maintained  at  the  cost  of  the  adjacent 
owners. 

Foundation. 

All  of  the  wood,  asphalt,  and  a  portion  of  the 
block-stone  pavements  of  Paris  are  laid  upon  a  specially 
prepared  cement-concrete  foundation,  which,  under  the 
same  conditions,  is  the  same  for  all. 

By  the  requirements  of  the  contracts  the  concrete 
must  be  composed  of  two  parts  by  measure  of  pebbles 
and  one  part  of  sand,  with  which  the  cement,  generally 
Portland,  must  be  mixed  in  the  following  proportions, 
by  accurate  measurement  and  weight : 

Pebbles,  by  measure I  cubic  yard 

Sand,        "          "      i     " 

Portland  cement,  by  weight   420  pounds 

None  of  the  pebbles  must  be  more  than  2^  inches 
nor  less  than  3/4-inch  in  diameter;  they  must  be  made 
perfectly  clean  by  abundant  washing.  The  sand  must 
be  free  from  all  earthy  matter  and  be  screened  so  as  to 
contain  no  grains  less  than  1/12  nor  more  than  1/6 
inch  in  diameter.  The  Portland  cement  is  thoroughly 
tested  before  being  accepted. 


PA  VEMEKTS   OF  PARIS.  73 

The  concrete  must  be  made  on  movable  beds  as 
near  as  possible  to  the  point  where  it  is  to  be  used, 
the  pebbles,  sand,  and  cement  being  mixed  dry  with 
shovels  in  such  way  as  to  insure  an  intimate  mixture. 
Water  is  added,  and  the  concrete  shovelled  at  once  on 
to  the  ground  prepared  to  receive  it.  It  is  then 
brought  up  to  grade  and  the  surface  made  even. 

After  not  less  than  three  days  a  coating  of  cement 
and  sand  about  an  inch  thick  is  spread,  and  the  sur- 
face made  perfectly  smooth  and  even.  This  mixture 
is  in  the  proportion  of  760  pounds  of  Portland  cement 
to  a  cubic  yard  of  sand. 

This  concrete  foundation  has  uniformly  a  thickness 
of  6  inches,  including  the  cement  coating.  In  ex- 
ceptional cases,  where  the  bad  condition  of  the  earth 
below  demands  it,  the  foundation  is  made  7  or  8 
inches  thick. 

Maintenance  of  Street  Pavements. 

It  is  assumed  that  the  wear  of  a  pavement  depends, 
first,  on  the  number  of  vehicles  using  it;  second,  on 
their  weight ;  third,  on  their  rate  of  speed.  These 
three  causes  act  simultaneously  in  wearing  the  pave- 
ments of  Paris  to  a  degree  not  exceeded  in  any  city  of 
the  world.  The  effect  of  the  numerous  three-horse 
omnibuses  is  specially  noticeable.  Their  weight,  which 
amounts  to  12,000  pounds  when  fully  loaded,  their 
speed  varying  from  54  to  6^  miles  per  hour,  and  their 
frequent  stops,  all  combine  to  make  them  a  very 

f         ~  OP  THE 

'UNIVERSITY/ 


74  ROADS  AND    PAVEMENTS  IN  FKANCE. 

destructive  agent.     The  speed  of  the  public  cabs  has 
also  sensibly  increased  within  the  past  fifteen  years. 

Different  Kinds  of  Pavement. 

Area  Jan.  i,  1894.  Per  cent. 

1.  Block-stone 7,541,258  sq.  yds.  71.5 

2.  Macadam 1,724,632    "      "  16.3 

3.  Asphalt 402,394"-     "  3.8 

4.  Wood 886,236   "      "  8.4 


10,554,520   *  100. o 

All  of  the  pavements  of  Paris  fifty  years  ago  were 
either  cobble-stone,  block-stone  or  macadam,  the  for- 
mer in  those  sections  where  travel  was  heaviest,  and 
the  latter  where  travel  was  relatively  lighter.  As 
travel  increased  in  the  streets  with  macadam  pave- 
ment the  wear  and  consequent  cost  of  maintenance 
increased  proportionally,  until  in  any  given  street  it 
became  evidently  more  economical  to  substitute  the 
more  costly  but  durable  block-stone,  with  its  moderate 
annual  cost  of  maintenance,  in  place  of  the  macadam, 
with  its  rapidly  increasing  annual  outlay  for  repairs. 
To-day  71  per  cent  of  the  street  pavement  of  Paris  is 
of  block-stone,  and  16  per  cent  is  of  macadam. 

The  desire,  however,  in  certain  sections  and  streets 
for  a  pavement  which  would  obviate  the  noise  of  the 
one  and  the  mud  and  dust  of  the  other  has  led  to  the 
introduction  first  of  asphalt  and  later  of  wood.  The 
experiments  with  asphalt  date  from  1837,  but  it  was 


PA  VFMENTS   OF  PARIS.  75 

not  until  1855  that  the  mode  of  construction  in  use 
to-day  was  first  applied. 

The  first  wood  pavements  were  laid  in  1881. 

On  the  1st  January,  1894,  the  asphalt  pavements 
represented  3.8  per  cent  and  the  wood  pavements 
8.4  per  cent  of  the  whole  pavement  of  Paris. 

The  tendency  to-day  is  to  substitute  asphalt  and 
wood,  mainly  the  latter,  for  block  stone  and  macadam, 
especially  for  macadam.  In  certain  outlying  parts  of 
the  city  macadam  will  still  be  retained,  and  in  others, 
from  the  nature  of  the  traffic,  block  stone  will  still 
be  preferred,  but  the  use  of  wood  is  decidedly  on  the 
increase. 

On  the  1st  January,  1894,  the  total  area  of  pave- 
ments of  all  kinds  was  21,516  square  yards  greater 
than  on  January  I,  1893;  but  the  area  of  the  block- 
stone  pavement  had  during  the  year  decreased 
31,215  square  yards  and  that  of  macadam  25,000 
square  yards,  while  that  of  wood  had  increased  77,381 
square  yards,  and  during  the  year  1894  it  had  fur- 
ther increased  more  than  124,000  square  yards. 

The  area  of  asphalt  had  increased  during  the  year 
1893  only  2800  square  yards. 

Wood  pavement  is  obviously  the  favorite  one.  Its 
advantages  as  compared  with  block  stone  and  mac- 
adam have  already  been  stated ;  it  is  smooth,  noise- 
less, agreeable  to  drive  over,  easily  kept  clean,  and  is 
rapidly  relaid  when  worn  out. 

Asphalt  has  all  of  these  advantages,  but  has  the 
disadvantage  of  being  rather  more  slippery  when  wet. 


76  ROADS  AND    PAVEMENTS  IN  FRANCE. 

Its  use  is  in  general  restricted  to  narrow  streets,  less 
open  to  the  sun  and  winds. 

Wood  is  in  general  laid  on  the  broader  streets,  to 
which  the  sun  and  winds  have  free  access. 

Neither  asphalt  nor  wood  is  considered  a  suitable 
pavement  for  streets  where  the  grade  exceeds  4  feet 
in  100.  This  condition  is  the  more  necessary  in 
Paris,  where  all  horses  at  all  seasons  are  shod  smooth 
— a  local  custom,  the  reason  for  which  is  not  apparent, 
as  there  seems  to  be  no  law  requiring  it,  It  un- 
doubtedly diminishes  the  wear  on  both  asphalt  and 
wood,  but  necessitates  the  sprinkling  of  sand  or  gravel 
wherever  the  surface  becomes  slippery  from  any  cause. 

I.  BLOCK-STONE  PAVEMENT. 

The  area  is  7,541,258  square  yards.  It  is  main- 
tained partly  by  contract,  and  partly  by  the  city 
directly  with  the  force  of  the  street  department. 
The  number  permanently  employed  in  this  work  is 
about  444,  divided  into  75  gangs  ("  brigades  "),  com- 
prising together  43  inspectors,  84  foremen,  and  317 
ordinary  paviors.  The  wages  per  'month  of  26  days 
of  10  hours  each  are  as  follows — 

Inspectors  of  the  first  class $33 

"    "   second  " 31 

Foreman 30 

Pavior  of  the  first  class 29 

"    "  second  "    28 

Helpers  (five  classes) $25  to  28 


BLOCK-STONE  PA  VEMENT. 


77 


Construction  and  Maintenance. 

All  wholly  new  pavement  is  laid  by  contract. 
The  maintenance  includes — 

1.  Reconstruction  with  the  substitution  of  new  stone 
for  old  ; 

2.  Large  repairs,    which  consist  in    taking  up  the 
old   pavement   and  in    repaving  with  selected   blocks 
that  are  more  or  less  worn ; 

3.  Small  repairs  in  such  spots  as  require  them. 
The  reconstructions  and  large  repairs  are  all  made 

by   contract.      In  the  case  of   reconstruction  the   old 

GRANITE  BLOCKS 


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blocks  are  carefully  sorted,  the  best  are  reserved  for 
large  repairs  elsewhere,  and  the  others  are  piled  in 
the  yards  to  be  recut,  or  to  be  discarded  entirely  if  no 
longer  utilizable. 

It  is  considered  necessary  that  not  less  than  1/35   of 


7  ROADS  AND    PA  VEMENTS  IN  FRANCE. 

the  entire  area  of  block-stone  pavement  should  be 
reconstructed  every  year  with  new  stone. 

All  of  the  older  pavements  were  laid  upon  the 
earth,  bedded  in  a  thin  layer  of  sand.  Within  a  few 
years,  however,  a  certain  area  has  been  laid  upon  the 
concrete  foundation  already  described,  in  a  layer  of 
sand  not  exceeding  3  inches  thick. 

The  results  have  been  so  satisfactory  that  the  gen- 
eral adoption  of  this  cement-concrete  has  been  limited 
only  by  its  cost.  In  1894  rather  more  than  1/22  of 
the  entire  block-stone  pavement  was  on  concrete  foun- 
dation. 

Kinds  of  Rock  and  Dimensions. 

The  standard  dimensions  now  approved  are  a 
length  \\  times  the  width  and  a  uniform  depth  of 
6J-  inches;  thus  the  sizes  6£'x  4",  7"  X  4f",  8"  X  5f, 
all  6^  inches  deep,  are  accepted. 

There  are  five  kinds  of  rock  used — the  porphyritic 
granite  of  the  Vosges  Mountains,  the  porphyry  from 
Belgium,  and  three  varieties  of  a  granular  quartzose 
rock  (gres  quart zites],  more  or  less  compact. 

The  Belgian  porphyry  is  but  little  used  at  present, 
hard  and  durable  as  it  is,  because  it  tends  to  become 
polished  and  slippery  under  wear.  This  is  a  point 
of  more  importance  perhaps  in  Paris  than  elsewhere, 
since  all  horses  there  are  shod  perfectly  smooth  at 
all  seasons. 

The  Vosges  granite  and  the  hardest  of  the  quartz- 


BLOCK-STONE   PAVEMENT.  79 

itzes  have  given  the  most  satisfactory  results,  but  the 
softer  quartzites  have  been  most  used  in  the  past  as 
being  the  least  costly.  The  city  owns  and  works 
some  quarries,  but  relies  on  them  mainly  as  a  means 
of  determining  the  proper  cost  of  the  stone  and  of  de- 
feating any  combination  of  the  contractors. 

Nearly  all  of  the  stone  used  is  furnished  by  con- 
tractors, who  are  required  to  deliver  it  in  one  or  other 
of  the  eleven  depots  or  yards  where  it  is  to  be  stored. 
A  sufficient  force  is  employed  to  receive  it,  and  at 
the  same  time  to  rigorously  inspect  each  block  and  to 
reject  all  that  are  deficient  in  quality  of  stone,  exact- 
ness of  dimensions,  or  perfection  of  cutting. 

Contract  for  Laying  Block-stone  Pavement. 

All  of  the  contracts  covering  the  block-stone  pave- 
ments of  Paris  extend  over  the  same  period.  The 
last  were  ,  for  2^  years  and  expired  July  I,  1895. 
The  form  of  the  contract  was  the  same  in  all,  but  in 
general  the  paving  of  each  of  the  twenty  wards 
(arrondissenients)  was  the  subject  of  a  separate  bid 
and  contract,  and  no  more  than  two  contracts  were 
awarded  to  any  one  bidder. 

The  probable  expenditure  under  each  of  these 
eighteen  contracts  is  stated  before  the  bidding,  but 
this  is  not  made  binding  upon  the  city  as  a  condition 
of  the  contract. 

The   contract   is  very  full   and   specifies  in  great 
detail  the  materials  to  be  used,  the  kind  of  work  that 


80  ROADS  AND   PAVEMENl'S  IN  FRANCE. 

may  be  required,  the  manner  in  which  it  shall  be  done, 
etc.  Attached  to  it  is  an  elaborate  schedule  of  prices 
of  the  different  kinds  of  labor,  of  the  several  materials 
used  (except  paving-blocks),  of  recutting  old  blocks, 
of  all  excavations,  etc.  The  several  bids  are  made  at 
a  greater  or  less  discount  from  this  schedule  of  prices, 
which  discount  applies  to  every  item  of  the  schedule. 
In  the  last  contracts  this  discount  ranged  from  24  to 
38  per  cent,  averaging  about  33  per  cent. 

The  contractor  must  do  the  work,  whatever  may  be 
required,  at  the  time  ordered. 

The  rate  of  work  (new  or  reconstructions)  must  be 
50  linear  feet  a  day,  whatever  the  width  of  the  street. 
In  addition  five  days  are  allowed  for  preparatory 
work  if  the  pavement  is  to  be  laid  in  sand  simply, 
and  twelve  days  if  to  be  laid  on  concrete  foundation. 

The  penalty  is  $4  a  day  if  the  work  is  not  com- 
pleted within  the  prescribed  time.  If  the  delay  is 
more  than  five  days,  the  engineer  may  complete  the 
work  at  the  expense  of  the  contractor. 

The  process  of  reconstructing  an  old  pavement  is 
very  simple.  The  contractor  removes  the  old  pave- 
ment and  carts  the  blocks  to  the  proper  yard  to 
be  sorted.  He  receives  and  transports  the  new 
blocks  to  be  laid.  The  old  sand  is  picked  and  fresh 
sand  added  as  may  be  required.  The  new  blocks 
are  placed  in  position  and  remain  uncovered  till  in- 
spected and  approved  by  the  superintendent  or  over- 
seer. The  joints  are  then  filled  full  with  dry  sand 


MA  CAD  AM  PA  VEMENT.  8 1 

by  thorough  brushing.  The  whole  surface  is  well 
pounded  with  a  paving- beetle  weighing  about  75 
pounds.  A  top  layer  i£  inches  thick  of  sand  is 
spread,  and  by  means  of  water  and  brooms  all  joints 
are  carefully  filled.  This  process  is  continued  till 
water  flows  over  the  surface  without  penetrating  any 
of  the  joints. 

If  the  pavement  is  to  be  laid  on  a  concrete  founda- 
tion, the  earth  upon  which  the  foundation  is  to  rest 
must  always  be  previously  pounded,  watered,  and 
puddled  with  care.  The  city  may  roll  it  at  its  own 
expense.  The  contractor  lays  the  concrete  founda- 
tion as  described  on  page  72.  Upon  this  foundation 
a  3-inch  layer  of  sand  is  spread  in  which  the  blocks 
are  bedded.  The  joints  are  sometimes  filled  with  a 
fluid  mortar  of  Portland  cement  and  sand  instead  of 
simple  sand  alone. 

II.   MACADAM  PAVEMENT. 

The  area  of  macadam  pavements  is  1,724,632  sq. 
yards. 

They  are  maintained  almost  entirely  by  the  city 
directly  with  the  force  of  the  street  department,  the 
material  only  being  furnished  by  contract,  delivered 
either  in  depots  or  on  the  street  where  required. 

The  number  of  men  permanently  employed  is  886, 
comprising  6  inspectors,  69  foremen,  and  81 1  ordinary 
roadmen.  In  addition  some  230  assistant  roadmen 
are  more  or  less  permanently  employed,  as  occasion 
requires. 


82  ROADS  AND   PAVEMENTS  IN  FRANCE. 

The  wages  per  month  of  26  days  of  10  hours  each 
are  substantially  the  same  as  those  given  on  page  76. 

The  roadmen  are  in  gangs  of  10  or  12  under  a  fore- 
man. 

The  mode  of  construction  and  repair  of  a  macadam 
pavement  has  been  already  described  (pages  24-50)  in 
sufficient  detail,  and  it  is  only  necessary  here  to  note 
the  special  application  of  it  to  the  streets  of  Paris. 

The  system  of  ''general  recharging,"  that  is,  of  re- 
storing to  the  pavement,  at  intervals  of  three  or  four  or 
perhaps  ten  years,  the  material  lost  by  ordinary  wear, 
has  been  substituted  for  the  older  system  of  "patch- 
work repair."  The  latter  is  now  used  only  for  the 
filling  of  holes  and  the  preserving  of  an  even  surface. 

A  recharging  of  about  4  inches  thick  is  preferred  as 
being  done  under  the  best  conditions,  but  circum- 
stances may  necessitate  one  of  2  to  3  inches,  or  one 
even  of  6  to  7  inches. 

The  work  of  repair  is  spread  through  nine  months 
of  the  year  in  order  to  give  steady  employment  to 
the  force  and  to  fully  utilize  the  steam-rollers.  To 
this  end,  every  spring  and  autumn  a  well-considered 
"plan  of  campaign"  is  determined  upon  to  be  carried 
out  by  the  several  engineers. 

The  city  owns  five  steam-rollers,  two  of  which 
weigh  about  58,000  Ibs.  each,  one  about  63,000  Ibs., 
one  40,000  Ibs.,  and  one  36,000  Ibs.  They  are  in 
constant  use  from  about  the  1st  of  March,  when  frosts 
are  no  longer  to  be  feared,  up  to  August,  and  again 


?     *- 

•II  VERSITT-. 
MA  CAD  AM-  PA  CEMENT.  83 

from  the  middle  of  September  to  the  end  of  Novem- 
ber. Necessary  repairs  are  made  in  the  shops  of  the 
street  department.  The  stone  used  in  the  construc- 
tion and  repair  of  this  pavement  is  almost  exclusively 
of  three  kinds,  viz.,  flints,  compact  millstone  grit, 
and  porphyry.  Porphyry  is  clearly  the  best  material 
available,  and  but  for  its  greater  cost  would  be  the 
only  stone  used ;  it  is  reserved  for  streets  subjected 
to  heavy  travel. 

The  cost  of  construction  of  a  macadam  pavement, 
including  all  charges  for  material,  labor,  rolling,  and 
general  expense,  was,  for  the  year  1893,  $0.80  per 
square  yard  where  flints  only  were  used,  $1.15  where 
millstone  grit  and  flints  were  used,  and  $1.34  where 
porphyry  and  flints  were  used. 

The  cost  of  maintenance  for  the  same  year  was 
$0.45  per  square"  yard  as  a  general  average  of  all  of 
the  macadam  pavement.  In  streets  where  the  travel 
is  heavy  the  cost  would  be  much  greater,  and  in  fact 
the  higher  annual  cost  of  maintaining  the  macadam 
pavement  in  proportion  to  the  amount  of  travel  is 
one  principal  reason  given  for  the  substitution  for  it 
of  one  of  the  three  other  kinds  of  pavement,  accord- 
ing to  the  requirements  in  each  case.  In  1893  the 
sum  of  about  $2,260,000  was  appropriated  for  such 
change  where  the  annual  cost  of  maintaining  the  mac- 
adam pavement  exceeded  $0.50  per  square  yard,  and 
an  additional  sum  of  $1,254,000  where  the  change 
was  made  for  other  reasons. 


84  ROADS  AND    PAVEMENTS  IN  FRANCE. 

Under  the  system  of  general  rechargings,  as  has 
already  been  stated,  such  repairs  as  are  made  during 
the  period  between  successive  rechargings  are  strictly 
confined  to  the  filling  of  holes  and  the  preserving  of  an 
even  surface  of  the  roadway.  In  some  of  this,  as 
well  as  in  other  operations,  the  roadmen  work  sepa- 
rately, each  within  his  section.  Several  times  a  day, 
according  to  the  weather,  they  scrape  off  the  soft  or 
fluid  mud  or  sweep  off  the  dust.  These  scrapings 
and  sweepings  are  collected  in  the  gutters,  and  are 
there  washed  in  a  stream  of  hydrant  water  in  such 
way  that  the  fine  mud  is  carried  into  the  sewers  and 
the  coarser  sand  is  left  behind,  to  be  removed  for 
other  uses. 

The  same  roadmen  are  also  required  to  water  the 
streets  frequently  in  dry  weather  with  hose  from  the 
hydrants,  and  on  streets  where  there  is  much  travel 
to  wash  them  every  five  or  six  days  with  an  abun- 
dance of  water  and  to  thoroughly  sweep  or  scrape  them. 
This  washing  is  always  done  in  the  morning,  as  soon 
as  the  travel  becomes  sufficiently  active  to  loosen  the 
mud  and  facilitate  the  sweeping. 

The  sweeping  is  done,  so  far  as  circumstances  ad- 
mit, by  sweeping-machines,  each  of  which,  drawn  by 
one  horse,  is  capable  of  cleaning  5400  square  yards  an 
hour,  and  is  equivalent  to  the  work  of  ten  men. 
One  hundred  machines  are  employed  on  the  macadam 
pavements  alone. 


ASPHALT  PAVEMENT.  85 

III.  ASPHALT  PAVEMENT. 

The  area  of  asphalt  pavement  is  about  368,000 
square  yards. 

It  was  adopted  as  a  substitute  for  block-stone  and 
macadam,  in  order  to  get  rid  of  the  noise  of  the  for- 
mer and  of  the  mud  and  dust  of  the  latter.  It  is 
noiseless  and  free  from  mud  and  dust,  and  on  this 
account  well  suited  for  the  immediate  vicinity  of 
dwelling-houses,  public  buildings,  schools,  hospitals, 
etc.  Its  disadvantage,  however,  is  that  it  becomes 
slippery  during  a  light  rain,  and  must  consequently 
be  kept  perfectly  clean.  When  the  surface  becomes 
slimy  it  must  be  well  washed  with  an  abundance  of 
water  and  lightly  sanded.  The  care  of  it  demands 
more  labor  and  consequent  expense  than  the  care  of 
block-stone  pavement.  The  same  is,  however,  true 
of  wood  pavement,  the  surface  of  which  requires  the 
same  care  and  nearly  the  same  expense. 

At  one  time  there  was  a  prejudice  against  asphalt, 
for  the  reason  that  it  softened  during  hot  weather 
and  became  disintegrated  by  severe  cold.  These  de- 
fects have  been  to  a  large  extent  corrected  by  a 
proper  mixture  of  different  asphalt  rocks,  and  also  by 
the  adoption  of  the  foundation  of  cement-concrete. 

Asphalt  is  used  not  only  for  the  roadways,  but,  in 
a  somewhat  modified  form,  for  the  sidewalks;  in  fact 
it  is  the  material  almost  exclusively  employed  for 
the  latter.  Thus  the  area  of  asphalt  sidewalks  is 


86  ROADS  AND    PAVEMENTS  IN  FRANCE. 

about  4,494,000  square  yards  out  of  a  total  area  of 
5,289,430  square  yards,  that  is,  85$  of  all  the  side- 
walk pavement  of  Paris. 

The  street-pavement  proper  is  only  402,394  sq. 
yds.,  that  is,  T£%  of  street  pavements  of  all  kinds. 

Both  sidewalk  and  street  pavements  are  all,  with 
some  unimportant  exceptions,  built  and  maintained 
by  contract.  The  present  contract  is  for  five  years 
from  March  1894,  and  gives  in  detail  the  requirements 
as  to  the  quality  and  character  of  the  materials  used, 
the  mode  of  construction,  etc. 

The  street-pavements  are  made  of  the  natural 
asphalt  rock  alone. 

The  sidewalks  are  made  of  a  mixture  of  the  same 
asphalt  rock  with  natural  bitumen  and  sand. 

Asphalt  Rock. 

The  contract  calls  for  the  natural  asphalt  rock  which 
occurs  in  certain  specified  localities  in  Switzerland, 
Savoy,  the  Department  of  Card  in  the  east  of  France, 
and  also  in  Sicily.  It  must  be  a  homogeneous  lime- 
stone, of  brown  color  and  with  a  fine  grain,  having  a 
quite  compact  texture  and  be  uniformly  impregnated 
with  natural  mineral  bitumen  in  such  way  as  to  show 
no  parts  either  black  or  white.  It  must  be  entirely 
free  from  iron  pyrites  and  contain  not  more  than  2%  of 
clay.  All  parts  of  the  rock  which  contain  less  than 
5$  of  natural  bitumen  are  rejected. 

The   rock  from   different  localities  differs   in   com- 


ASPHALT  PAVEMENT.  87 

position,  compactness,  and  in  percentage  of  bitumen, 
that  generally  used  containing  from  7$  to  13$.  It 
is  mixed  in  such  proportions  as  to  give  the  percentage 
of  bitumen  desired. 

Street  Pavement 

The  contract  requires  that  the  ground  asphalt  rock 
shall  contain  at  least  6$  and  at  most  13$  of  its  weight 
of  bitumen,  the  exact  amount  to  be  determined  in 
each  case.  Also,  that — 

ist.  The  rocks  mixed  shall  differ  only  in  their 
percentage  of  bitumen,  and  that  no  part  shall  contain 
less  than  5$. 

2d.  The  different  rocks  must  be  mixed  before  being 
ground. 

Asphalt  obtained  from  the  tearing  up  of  old  pave- 


FlG.   12. 

ments  shall  not  be  mixed  with  fresh  rock  or  be  used 
at  all  for  this  work. 

The  asphalt  rock  is  ground  cold  to  a  powder  as 
fine  and  homogeneous  as  possible  with  the  most  per- 
fect rolls ;  this  powder  must  pass  through  a  screen 
with  i/io-inch  mesh.  It  is  then  heated  in  continually 
revolving  cylinders,  and  kept  at  a  temperature  of  from 


88  ROADS  AND   PA  VEMENTS   IN  FRANCE. 

248°  F.  to  268°  F.  until  all  moisture  has  been  evapo- 
rated. 

The  powdered  rock,  while  still  hot,  is  loaded  at 
once  into  carts,  so  covered  as  to  prevent  as  much  as 
possible  the  escape  of  heat,  and  brought  promptly  to 
the  street  where  the  pavement  is  being  laid. 

The  6-inch  Portland  cement-concrete  foundation, 
such  as  heretofore  described,  has  already  been  laid. 
The  asphalt  layer,  when  finished,  is  generally  2  inches 
thick. 

The  powdered  rock  is  quickly  spread  upon  the 
foundation,  as  soon  as  it  arrives,  levelled  with  rakes, 
pounded  with  heated  iron  rammers  at  first  carefully 
and  lightly,  smoothed  with  a  hot  iron  tool,  pounded 
again  with  more  force,  again  smoothed  with  the  hot 
tool,  and  pounded  a  third  time  thoroughly.  The  com- 
pression is  completed  by  means  of  a  roller  weighing 
not  less  than  1 100  Ibs.  passed  repeatedly  over  the 
surface  till  the  layer  is  quite  cold. 

The  cost  of  constructing  an  asphalt  pavement,  in- 
cluding the  6-inch  foundation  of  Portland  cement 
concrete  and  a  2-inch  layer  of  compressed  asphalt, 
varies  from  $2. 84  to  $3. 10  per  square  yard,  the  concrete 
foundation  costing  75  to  80  cents,  The  expenditure 
in  Paris  for  maintenance  and  large  repairs  in  1893  was 
a  general  average  of  37  cents  per  square  yard. 
Sidewalks. 

The  excellence  of  the  sidewalks  of  Paris  is  well 
known. 


ASPHALT  SIDEWALKS.  89 

The  material  used  for  them  is  known  as  "  bitumi- 
nous mastic,"  and  is  composed  of  finely  powdered 
asphalt  rock  mixed  hot  with  a  varying  proportion  of 
hot  bitumen  similar  to  that  contained  in  the  natural 
rock. 

The  rock  is  powdered  in  the  manner  already  de- 
scribed. The  contract  requires  that  it  be  melted  and 
stirred  during  at  least  six  hours  with  a  quantity  of 
mineral  bitumen  sufficient  to  form  a  mastic  which, 
when  cold,  will  be  a  homogeneous  mass  slightly 
elastic,  but  not  softening  at  a  temperature  of  104°  F. 
This  mastic  while  still  hot  and  in  a  pasty  condition 
is  run  into  moulds,  forming  cakes  that  weigh  about  56 
Ibs.  It  must  contain  not  less  than  15$  nor  more 
than  1 8$  of  bitumen. 

There  are  two  qualities  of  the  bituminous  covering 
for  sidewalks.  The  first  contains  by  weight — 

Bituminous  mastic 100  parts 

Bitumen  for  fluxing 6     * ' 

Sand   60     " 

The  second  contains — 

Bituminous  mastic 100  parts 

Bitumen  as  flux 10     '  * 

Sand 60     " 

170  parts 

And  an  equal  quantity  of  bitumen  from 
old  sidewalks,  carefully  freed  from 
sand  or  other  adherent  foreign  matter  170  " 

When  a  sidewalk  is  to  be  laid,  the  ground  is  first 


90  ROADS  AND    PAVEMENTS  IN  FRANCE. 

thoroughly  pounded  and  puddled  while  being  graded 
to  a  slope  of  I  in  50  from  the  inside  toward  the  curb. 

Upon  this  the  foundation  of  hydraulic  or  Portland 
cement-concrete,  4  inches  thick  including  a  surface 
coating  of  1/3  inch  thick  of  cement,  is  accurately  laid, 
and  allowed  to  become  perfectly  dry. 

The  bituminous  covering  is  then  prepared  at  the 
furnaces.  The  mastic  is  broken  into  pieces  1/2  in.  to 
i  in.  in  diameter,  remelted  with  the  5$  or  10$  of  pure 
bitumen,  and  the  60$  of  sand  fine  and  perfectly  dry 
is  added  gradually  to  the  mixture  in  the  heated  fur- 


JASPHALT 

T 
CONCRETE 


FIG.  13. 

nace  at  intervals  during  the  eight  hours  of  heating 
and  stirring.  During  this  time  the  mass  must  be  kept 
at  a  temperature  of  not  less  than  280°  F.  nor  more 
than  360°  F.,  and  be  constantly  stirred. 

This  mixture  when  ready  is  run  hot  into  heated 
portable  cylinders  holding  about  I  ton,  and  carried 
at  once  to  the  point  where  it  is  to  be  used.  It  is 
kept  always  at  the  same  temperature  by  a  small  fur- 
nace under  the  cylinder,  and  is  frequently  stirred  dur- 
ing transit  and  up  to  the  moment  of  use. 

The  bituminous  mixture  is  then  spread  and,  while 
still  hot  and  plastic,  made  perfectly  even  and  smooth 
with  wooden  tools.  A  very  little  dry  sand  is  sprinkled 
over  it,  and  in  twenty  minutes  the  surface  becomes 
quite  hard,  and  can  be  walked  upon. 


WOOD    PAVEMENT.  9 1 

This  bituminous  covering  is  generally  3/5  inch 
thick. 

Bitumen. 

The  bitumen  used  is  always  the  natural  mineral 
product  derived  directly  from  the  asphalt  rock  or 
similar  sources,  and  must  come  from  certain  specified 
localities.  It  must  not  contain  any  foreign  substance, 
or  water  or  clay  or  volatile  oils ;  when  heated  for  48 
hours  at  a  temperature  of  230°  F.  it  must  not  lose 
more  than  3$  of  its  weight.  It  must  be  viscous  at 
ordinary  temperature,  never  becoming  brittle  nor 
fluid ;  drawn  out  into  threads  it  must  break  only 
when  the  thread  is  very  slender. 

The  bitumen  from  Trinidad  is  also  used,  but  owing 
to  the  amount,  sometimes  as  much  as  33$,  of  fine 
clay,  sand,  and  vegetable  mixed  with  it,  it  must  first 
be  thoroughly  refined. 

Sand. 

The  sand  for  this  use  must  be  entirely  free  from 
earthy  and  foreign  matters,  it  must  be  dried  and  freed 
by  successive  screenings  of  all  grains  less  than  1/12  or 
more  than  1/6  inch  in  diameter. 

IV.  WOOD  PAVEMENT. 

Wood  pavement  was  adopted,  like  asphalt,  to  secure 
a  less  noisy  and  more  even  pavement  than  block  stone 
and  macadam. 

XJNI VERSITY  ' 

OF 


92  ROADS  AND   PAVEMENTS  IN  FRANCE, 

Its  area  is  somewhat  more  than  1,000,000  square 
yards,  which  is  about  one  tenth  of  the  total  pavement 
of  all  kinds. 

The  first  wood  pavement  was  laid  in  1884  under 
contracts  with  certain  companies,  by  the  terms  of  which 
they  were  to  bear  the  first  cost  of  it,  to  maintain  it 
satisfactorily  during  the  eighteen  years  of  the  con- 
tract, and  at  the  end  of  the  contract  to  relay  it  all  anew. 
As  compensation  they  were  to  receive  annually  during 
the  eighteen  years  $0.40^  a  square  yard  of  pavement 
laid  as  representing  the  first  cost  and  interest  thereon, 
and  in  addition  thereto  as  representing  maintenance 
$0.42  to  $0.50  a  square  yard,  according  to  the  amount 
of  travel.  For  the  purposes  of  this  calculation  the 
first  cost  of  construction,  including  also  the  cost  of 
removing  the  former  pavement,  was  assumed  to  be 
$3.85  per  square  yard. 

At  present  and  for  some  years  past  all  of  the  new 
pavements  have  been  laid  by  the  city  directly. 

The  cost  of  substituting  a  wood  pavement,  including 
the  6-inch  cement-concrete  foundation,  for  block  stone 
and  macadam  is  given  as  follows : 


Wood  Pavement.       Wood  Pavement.      Wood   Pavement 
Kind  of  Pavement.  6  in.  thick.  4!  in.  thick.  4  in.  thick. 

Per  sq.  yd.  Per  sq  yd.  Per  sq.  yd. 

Block-stone $3-12^  $2.63  $2.46 

Macadam 3.46  2.90  2.72 

The  tendency  to-day  is  to  substitute,  in  certain 
sections  of  the  city,  wood  and  asphalt  for  block  stone 
and  macadam.  In  general,  wood  is  laid  in  streets 


WOOD   PAVEMENT,  93 

that  are  broad,  open  to  the  sun  and  air,  and  where 
travel  is  constant.  The  expectation  is  that  the  pave- 
ment shall  wear  out  and  not  perish  from  decay.  The 
durability  of  the  pine  blocks  as  originally  laid  is  from 
eight  to  nine  years  upon  the  boulevards  and  main 
streets,  where  the  travel  is  constant  and  heavy.  The 
blocks  are  often  worn  down  in  such  places  to  one  half 
of  their  original  depth.  The  pavement  of  the  Place 
de  la  Concorde,  for  instance,  was  renewed  in  March 
1895.  It  was  laid  in  September  1885.  Had  all  of  the 
blocks  been  homogeneous  the  pavement  would  have 
lasted  much  longer.  The  failure  of  isolated  blocks 
made  the  pavement  uneven  before  it  was  worn  down 
to  the  extreme  limit. 

The  wood  pavement  of  the  Place  Vendome  was 
renewed  in  May  1895,  after  seven  years'  wear. 

The  statement  of  the  annual  wear  of  the  following 
streets  is  from  official  sources: 

Decimals  of  I  Inch. 

Boulevard    des  Poissonniers  ) 

I 0.2908 

"Italians  ) 

Rue  de  Rivoli o.  1968 

Avenue   de   1'Opera 0.1572 

Rue  de  Castiglione o.  1257 

"     "  Londres o.  iioo 

Avenue  d'Antin o.  1060 

Place  de  1'Alma   0.0943 

Rue  de  la  Chausse"e  d'Antin .  0.0864 

Rue  de  Rome 0.0746 


94 


ROADS  AND   PAVEMENTS  IN  FRANCE. 


The  wood  is  used  in  its  natural  state,  no  treatment 
by  any  antiseptic  agent  to  prevent  decay  being  made. 
The  blocks,  it  is  true,  are  dipped  in  creosote,  but  this 
is  simply  to  protect  them  slightly  while  they  are  stored 
in  the  yard  awaiting  use.  It  is  of  no  value  after  they 
are  once  laid. 

All  of  the  wooden  pavements  to-day  in  Paris  are 
laid  upon  a  foundation  of  Portland  cement-concrete  6 


FIG.  14. 

inches  thick,  the  surface  of  which  is  made  perfectly 
smooth.  The  wooden  blocks  have  in  general  a  depth 
of  6  inches  and  an  exposed  surface  of  9  x  3i  inches. 
They  are  placed  in  rows,  with  a  space  of  7/16  inch 
between  two  successive  rows,  and  the  blocks  arranged 
so  as  to  break  joints.  Experiments  have  been  tried 
of  making  the  spacing  between  the  rows  1/4  inch,  and 


WOOD    PAVEMENT.  95 

even  1/8  inch  only,  in  order  to  secure  greater  solidity, 
but  the  results  are  not  stated. 

The  actual  laying  is  very  simple  and  rapid.  The 
blocks  are  placed  on  their  edges  within  easy  reach  of 
the  pavior,  who  with  a  hatchet  quickly  lays  each  block 
in  its  proper  place  in  the  row,  spacing  the  rows  as  he 
goes  on  by  strips  of  wood  of  the  required  thickness 
and  itj-  to  2  inches  broad  and  5  or  more  feet  long. 
These  he  lays  in  obliquely  with  their  ends  projecting 
above  the  surface,  so  that  they  may  be  readily  with- 
drawn when  some  half-dozen  rows  have  been  laid,  and 
used  again  as  the  work  proceeds. 

As  soon  as  they  are  withdrawn  hot  coal-tar  is  poured 
into  the  spaces  between  the  rows  so  as  to  fill  about  i 
inch  of  the  6  inches  of  depth.  This  is  done  in  order 
to  hold  the  blocks  more  firmly  in  place  during  the  sub- 
sequent operations,  and  not  as  a  preservative  of  the 
wood. 

The  5  inches  remaining  of  the  6  inches  of  depth  are 
at  once  filled  carefully  with  a  fluid  mixture  of  cement 
and  sand  in  the  proportion  of  750  to  850  Ibs.  of  Port- 
land cement  to  each  cubic  yard  of  sand. 

The  surface  of  the  pavement  is  then  covered  with  a 
thin  layer  of  coarse  gravel,  the  hardest  and  sharpest 
preferred,  in  order  that,  under  ordinary  travel,  the 
hard  particles  may  be  ground  into  the  fibres  of  the 
wood  and  make  the  surface  harder  and  less  slippery. 
They  penetrate  the  wood  to  the  depth  of  one  fourth  of 
an  inch  or  more,  and  materially  increase  the  durability 


96 


ROADS  AND   PAVEMENTS  IN  FRANCE. 


of  the  pavement  as  well  as  its  impermeability  to  water. 
When  the  pavement  is  first  laid  and  when  first  wet 
the  wood  swells,  and  the  expansion  manifests  itself  in 
a  lateral  pressure,  which  is  provided  for  near  the  curb- 
stone on  each  side  of  the  street  by  leaving  a  free  space 
of  2  inches  between  the  pavement  and  the  curb,  which 
space  is  later  filled  with  sand  as  required. 


SAND  2  Sil 


BLOCKS  PLACED 
LONGITUDINALLY 


FIG.   15.— Plan. 

Kinds  of  Wood. 

The  wood  first  used  was  Norway  spruce  or  fir. 
Later  the  more  or  less  resinous  pine  from  the  Landes, 
South  of  France,  has  been  much  used,  and  with  better 
results.  The  pitch-pine  from  Florida  is  considered 
more  durable  than  the  latter,  and  is  used  to  a  limited 
extent.  Within  the  last  three  or  four  years  experi- 


WOOD   PAVEMENT.  97 

ments  have  been  made  with  the  "  Jarrah  "  and 
"  Karri  "  woods  from  Australia,  the  "  Teak"  from 
Java,  the  so-called  "  Bois  de  fer  "  from  Borneo,  and 
the  "  Liem,"  from  Annam — all  of  them  much  harder 
and  more  compact  than  the  woods  heretofore  used. 
It  is  too  soon  to  expect  conclusive  results,  but  it  is 
believed  from  the  observations  already  made  that  one 
or  other  of  these  woods,  or  one  equally  hard  and 
homogeneous,  will  prove  more  economical  on  streets 
where  the  wear  is  greatest  than  any  of  the  woods  here- 
tofore used.  Great  care  is  taken  that,  whatever  be  the 
wood,  the  blocks  laid  in  any  one  street  shall  be  as 
nearly  homogeneous  as  a  strict  selection  can  insure. 
Could  they  all  be  absolutely  homogeneous,  the  wear 
would  be  uniform  and  the  formation  of  holes  due  to 
the  decay  or  giving  way  of  isolated  blocks  be  pre- 
vented. It  would  greatly  lengthen  the  life  of  a  pave- 
ment. 

As  has  been  already  stated,  the  standard  depth  of 
the  blocks,  that  is,  the  thickness  of  the  pavement,  is  6 
inches ;  but  on  several  streets  it  has  been  reduced  to 
4f  inches,  and  even  to  4  inches.  A  thickness  of  4j 
inches  is  apparently  quite  sufficient  in  streets  where 
the  travel  is  moderate  and  where  repairs  become  neces- 
sary, not  from  wear,  but  because  of  the  holes  due  to 
the  decay  of  isolated  blocks. 

When  a  pavement  must  be  entirely  renewed,  in  con- 
sequence of  wear  rather  than  of  decay,  a  certain  num- 
ber of  the  blocks  taken  up  may  still  be  perfectly  sound 


98  ROADS  AND   PAVEMENTS  IN  FRANCE. 

and  comparatively  little  worn.  In  order  to  utilize 
what  value  these  may  still  have,  they  are  carted  to  the 
yard  of  the  street  department  and  cleaned.  Then  by 
means  of  a  circular  saw  the  worn  part  of  each  block  is 
cut  off  evenly,  reducing  the  height  of  the  block  to  4}, 
4,  or  even  3  inches.  The  several  sizes  are  piled,  to 
be  used  again  on  streets  where  the  travel  is  light. 

If  the  trials  of  the  imported  hard  woods  prove  as 
successful  as  anticipated,  the  use  of  them  will  doubtless 
be  increased,  even  at  the  relatively  high  cost.  To 
bring  the  cost  within  satisfactory  limits  the  thickness 
of  the  pavement  may  be  made,  say,  4  inches  instead  of 
6  inches. 

Cost  of  Construction  and  Maintenance. 

p  Construction  Cost    Annual  Maintenance 

per  square  yard.         per  square  yard. 

Block-stone   $2.81  to  $3.85  $0.14 

Macadam 0.80°      1.34  O-44 

Asphalt 2.84"     3.10  0.37 

Wood 3.00  0.46 

The  above  figures  are  for  the  year  1893,  as  appears 
by  official  report. ~x~ 

Width  and  Convexity. 

Experience  has  shown  that  the  different  conditions 
to  be  satisfied  are  nearly  realized  by  giving  the  road- 

*  Notes  al'appui  du  Compte  des  Depenses   de  1'Exercise  1893. 
Monsieur  L.  Boreux,  1'Ingenieur  en  chef  de  la  Voie  publique. 


STREET  CLEANING. 


99 


way  such  a  convexity  that  the  cross   profile    of   the 
surface  is  parabolic.     v 

From  the  following  table  will  be  seen  the  propor- 
portion  of  roadway  and  sidewalk  in  streets  of  certain 
standard  widths,  as  well  as  the  convexity  usually 
adopted. 


"            ,        ' 

i  J3  O 

c      S£ 

rt.Sf^'o 

u  . 

Iff 

u^£s 

*ES|  . 

Total  Width  of  Street. 

*o  ^^O 

*j  jjjrjfe  «* 

o  S 

°.o3 

III 

|f|  1 

illli 

II 

Feet. 
32  8  (  10  met  ) 

Feet. 
21   64 

Feet. 

008-7 

Feet. 

Feet. 

c    c8 

3  •  b° 

30  36  (12  met  ) 

23  61 

I/C7 

7    87 

49  2(15  met  )   

29   52 

0/108 

1/57 

I  /^O 

98A 

65  6  (20  met  )  

TQ      'if) 

O6J.2 

1/6  1 

T  Q        TO 

Boulevards  and  Avenues 

i     45-92 
1     52.48 

0.741 
0.839 

1/62 
1/62 

j     59-04 

0.938 

1/63 

Exceptional  Streets  

1  .036 

(88.56 

1-377 

1/64 

Cleaning  and  Watering. 

Cleaning  comprises  three  general  divisions: 

1 .  The  removal  of  mud  and  household  refuse,  which 
is  done  by  contract. 

2.  Sweeping  and  watering,  which  is  done  exclusively 
by  the  street  department,  except  that  sand  is  furnished 
by  contract  as  well  as  the  use  of  some  of  the  sweeping- 
machines. 

3.  The  removal  of  snow  and  ice. 

The  surface  (streets  and  sidewalks)  cleaned  is  about 
18,894,000  square  yards.     The  total  expense  for  the 


100        KOADS  AND  PAVEMENTS  IN  FRANCE. 

year  1893  was  $1,850,611,  which  is  a  general  average 
of  nearly  10  cents  a  square  yard. 

The  removal  of  mud  and  of  household  refuse  is 
made  between  6.30  and  8.30  A.M.  from  April  I  to 
October  I,  and  between  7  and  9  A.M.  from  October  I 
to  April  i.  Each  house-owner  is  required  by  law  to 
furnish  from  9  P.M.  for  the  several  tenants  one  or  more 
receptacles  for  refuse  which  are  to  be  brought  out  each 
morning  onto  the  street  in  front  of  the  house  one 
hour  at  least  before  the  carts  come  by ;  as  soon  as 
emptied  they  are  taken  into  the  house. 

The  contractors  furnish  their  own  carts  for  the 
removal  of  this  refuse,  and  become  the  owners  of  it. 
They  generally  sell  it  to  farmers  or  kitchen  gardeners 
as  manure. 

This  refuse  is  said  to  be  a  good  fertilizer,  nearly 
equal  to  farm-yard  manure,  as  appears  by  the  follow- 
ing analysis : 

Percentage. 

Nitrogen o. 38 

Phosphoric  acid  . .  , . 0.41 

Potash 0.42 

Lime 2.57 

The  city  nevertheless  has  difficulty  in  disposing  of 
this  refuse,  due  mainly  to  the  objections  on  the  part 
of  adjacent  villages  to  the  use  of  it  within  their  ter- 
ritories or  to  the  carting  of  it  through  them.  Arrange- 
ments have  consequently  been  made  with  all  the 


STREET   CLEANING.  IO1 

principal  railways  radiating  from  the  city  for  transport- 
ing it  at  a  reduced  tariff  to  more  or  less  remote  points. 
The  total  amount  of  refuse  removed  in  the  year  1893 
was  1,050,000  "  tonnes;"  of  which  680,000  tonnes 
were  utilized  in  the  immediate  vicinity,  100,000  tonnes 
transported  on  the  river  to  distances  from  6  to  37 
miles,  and  270,000  tonnes  transported  by  railway. 

The  market  value  of  the  fresh  refuse  varied  in  1893 
from  I2J-  to  25  cents  a  cubic  yard,  taken  on  the  cart 
or  boat. 

The  total  expense  of  the  removal  of  all  kinds  of 
refuse,  including  the  street  sweepings  that  are  not 
washed  into  the  sewers,  was,  in  1893,  $377,186. 

Each  of  the  twenty  wards  is  made  the  subject  of  a 
separate  contract  for  a  period  of  five  years,  and  no  one 
contractor  is  awarded  more  than  four  of  these  con- 
tracts. The  contractor  furnishes  the  cart,  horse,  and 
driver.  The  city  furnishes  a  street-sweeper  to  assist 
in  loading,  a  woman  to  sweep  up  whatever  may  have 
fallen  when  the  refuse  barrels  are  emptied  into  the 
cart,  and  a  rag-picker,  who  remains  in  the  cart  and 
assists. 

The  expenses  attending  this  method  of  disposing  of 
the  refuse  at  more  or  less  remote  points — and  these  ex- 
penses under  the  new  contracts  are  23  per  cent  greater 
than  under  the  former  contracts — have  led  the  engi- 
neers to  study  more  carefully  the  methods  pursued 
elsewhere,  notably  in  England.  Within  the  last  two 
years  a  furnace  has  been  built  by  the  city  for  burning 


102         ROADS  AND   PAVEMENTS  IN  FRANCE. 

a  certain  amount  of  the  refuse,  and  although  the  results 
are  understood  to  be  satisfactory,  the  question  is  not 
considered  settled,  as  experiments  are  still  going  on. 

Street  Sweeping. 

The  sweeping  of  the  streets  is  done  by  hand  or  by 
sweeping-machines. 

The  force  engaged  comprises — 

Yearly  Pay. 

37  inspectors $360  to  396 

1 3 1  foremen 336   ' '  348 

6 12  roadmen 324 

1383   laborers 300   "  324 

95  I  women  sweepers 192    "216 

408  rag-pickers,  paid  24  cents  a  day  for  about 
three  hours'  labor. 


3522 

The  women  sweepers  are  required  to  work  only 
seven  hours  a  day.  The  rag-pickers  are  occupied  only 
while  the  carts  are  collecting  and  removing  the  house- 
hold refuse.  They  keep  whatever  of  value  they  find, 
which  is  estimated  to  be  about  twenty  cents  a  day. 
The  others  are  required  to  work  ten  hours  a  day. 

The  prescribed  routine  of  service  is  as  follows: 

4  to  6.30  A.M. — Sweeping  and  washing  of  the 
sidewalks  and  the  streets;  sprinkling  of  sand  where 
required ;  general  cleaning  of  the  urinals. 

6.30  to  8.30  A.M. — Removal  of  the  household  refuse 


STREET  CLEANING.      ...  1 03 

and  the  street  sweepings ;  continuation  of  the  above 
work. 

8.30  to  ii  A.M. — Picking  up  horse-droppings;  wash- 
ing of  the  gutters ;  watering  of  the  streets  by  watering 
carts  and  hydrant  hose ;  thorough  cleaning  and  disin- 
fecting of  the  urinals.  End  of  the  day  for  the 
women  sweepers. 

ii  A.M.  to  i  P.M.,  dinner. — If  circumstances  require 
it,  a  part  of  the  force  continue  work  and  dine  later. 

i  to  4  P.M.  (end  of  the  day). — Sweeping  by  the 
machines;  watering;  picking  up  horse-droppings; 
sweeping  of  sidewalks ;  thorough  cleaning  and  disin- 
fecting of  the  urinals ;  washing  of  benches,  etc. 

4  to  7  P.M. — Extra  service  with  extra  pay,  when 
necessary  for  sweeping,  watering,  washing  gutters,  or 
spreading  sand. 

7  to  9  P.M. — During  five  months  of  winter  spreading 
sand  on  the  asphalt  and  wood  pavements. 

When  the  streets  are  swept  during  a  dry  season 
they  are  first  watered  to  avoid  dust.  When  the  sur- 
face is  muddy,  it  is  well  watered  in  order  to  loosen 
the  mud.  During  a  rainy  time  the  sweeping-machines 
are  passed  several  times  in  succession  over  the  surface 
to  clean  it  and  remove  the  puddles  of  water.  When 
the  asphalt  or  wood  pavement  is  not  muddy,  it  is 
dried  by  the  rubber  scraper.  The  dry  sweeping^ 
are  removed  in  carts.  The  semi-fluid  ones  are  washed 
in  the  gutter  in  a  stream  of  hydrant  water  and  the 
fine  particles  carried  into  the  sewer.  The  coarse 


104        ROADS  AND   PAVEMENTS  IN  FRANCE. 

sand  is  reserved  to  be  used  elsewhere,  or  carted 
away. 

A  conspicuous  feature  is  the  great  abundance  of 
water  used  to  keep  the  streets  clean.  The  water  of 
the  Seine  is  pumped  into  reservoirs  and  is  used  for 
this  and  all  other  purposes  except  drinking. 

During  hot  or  dry  weather  the  streets  are  thor- 
oughly washed  clean — 

Block-stone  and  macadam  pavements  every  three 
days; 

Asphalt  pavements  every  two  days ; 

Wood  pavements  every  day. 

In  general  this  washing  is  done  between  4  and  8 
o'clock  in  the  morning.  The  gutters  are  washed 
twice  a  day,  and  the  pavements  are  sanded  as  often  as 
necessary  to  prevent  their  becoming  slippery. 

The  city  owns  394  sweeping-machines,  100  of 
which  are  assigned  to  the  care  of  the  macadam  pave- 
ments, 234  to  general -cleaning,  and  60  kept  in  reserve 
for  special  service. 

The  cleaning  of  the  sidewalks  is  done  entirely  by 
hand. 

Watering. 

The  watering  of  streets  is  done  wholly  by  the  road- 
men  engaged  in  cleaning  and  by  those  in  charge  of 
the  macadam  pavements,  and  either  by  means  of 
watering-carts  or  hydrant  hose.  Formerly  it  was  done 
by  watering  carts  only,  but  at  present  the  latter  method 


STREET   CLEANING.  IO$ 

is  adopted  wherever  practicable  as  being  the  cheaper ; 
the  cost  is  stated  to  be  about  one  half  of  that  by 
watering-carts. 

The  watering  begins,  in  ordinary  seasons,  on  the 
1 5th  March  on  the  macadam  pavements  and  ends 
on  the  1 5th  October;  and  on  other  pavements  it  begins 
April  ist  and  ends  September  3Oth. 

There  are  two  watering  periods  daily,  the  first  be- 
ginning at  5  A.M.  and  ending  at  10  A.M.  ;  the  second 
is  from  I  to  5  P.M.  In  very  warm  weather  the  first 
is  continued  until  n  A.M.,  and  the  second  extends 
from  noon  to  6  or  7  o'clock. 

The  area  watered  by  the  hydrant  hose  is,  however, 
as  yet  only  43^-  per  cent,  while  that  watered  by  carts 
is  56^  per  cent  of  the  whole. 


APPENDIX. 


CLASSIFICATION    OF    ROADS   IN    FRANCE.* 

The  roads  are  divided  into  six  classes,  viz.  : 

ist.  Routes  Nationales,  which  belong  to  the  state 
and  are  constructed  and  maintained  by  the  national 
government. 

2d.  Routes  Depart ementales,  which  belong  to  the 
several  departments  and  are  constructed  and  main- 
tained by  them. 

3d.  Chernins  Vicinaux  de  Grande  Communication. 
— These  roads  connect  and  may  pass  through  two  or 
more  communes,  and  are  maintained  by  the  communes 
interested  and  served,  with  additional  aid  from  the 
funds  of  the  department.  This  aid  is  authorized  by 
law,  and  is  always  depended  on.  The  roads  of  this 
class  are  intended  to  serve  almost  identically  the  same 
purposes  as  the  departmental  roads,  but  are  under 
quite  different  control  and  management — an  anoma- 
lous condition  which  will  doubtless  disappear  in  time. 

*  Dictionnaire  Administratif  des  Travaux  Publics.    A.  Debauve, 
Ingenieur  en  chef  des  Fonts  et  Chaussees.     Paris,  1892. 

1 06 


APPENDIX.  IO7 

4th.  Chemins  Vicinaux  de  Moyenne  Communication, 
or  d'  Inter et  Comnmn. — These  roads  connect  two  or 
more  communes,  but  do  not  have  the  importance  of  the 
roads  of  the  third  class.  They  are  maintained  largely 
at  the  cost  of  the  communes  interested,  but  are  con- 
trolled and  directed  by  the  administration  of  the  de- 
partment. 

5th.  Chemins  de  Petite  Communication,  or  Vicinaux 
Ordinaires,  are  of  still  less  importance  than  the  roads 
of  the  fourth  class.  They  are  maintained  by  the 
several  communes  separately,  under  the  supervision  of 
government  engineers. 

6th.  Chemins  Ruraux. — These  are  roads  of  the 
least  importance.  They  are  wholly  controlled  and 
maintained  by  each  commune,  without  any  interference 
on  the  part  of  the  national  or  departmental  government. 

Classes  numbers  3d,  4th,  and  5th  constitute  the 
CJicmins  Vicinaux,  which  may  be  described  as  "  parish" 
roads.  They  correspond  to  the  via  Vicinalis  of  the 
Romans,  and  connect  market  towns  with  each  other, 
and  hamlets  with  their  centres. 


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